After about a year of playing SWTOR on and off, I figured putting down some thoughts about it was long overdue. I'll admit upfront that most of my MMO experience comes from Star Wars Galaxies, which I played for about 3 years prior, so a lot of my comparisons stem from that, but I'll do my best to explain without assuming familiarity with SWG.
SWTOR is, despite the massive amount of hype it received prior to launch, not all that different from "traditional" MMOs. Sure, it's packaged in nice graphics, all-spoken dialog, and vast planets to explore, but at its heart it carries over the majority of the mechanics and features of WoW and similar games: Go kill so-and-so, retrieve what-have-you, etc., and you'll get some new armor or something. That's not really a bad thing, but it's something to know before playing. Anyone expecting a reinvention of the proverbial wheel for MMOs may be somewhat disappointed.
To start with, there's a lot to like about the graphical work in SWTOR. The worlds and characters take somewhat after their KOTOR predecessors, appearing "cartoonish" in an inobtrusive way. With a few exceptions (the roof of the Senate building on Coruscant, for instance,) the worlds look spectacular, with details down to the lighting on individual leaves and blades of grass. Hardware-wise, the game is far from demanding, and is perfectly playable on my old 310M-equipped laptop. As with most MMOs, the game is mostly CPU-bottlenecked, and my Phenom noticably restricts framerates at times, though never to the point of unplayability.
Having spent the majority of my time in-game in the open world questlines (with 1 character to 50 and a number of others at various stages of completion,) this is the part of the game I've played the most, and also the one I have the most issues with. But first, the good parts:
BioWare is known for its storylines, and SWTOR definitely lives up to these expectations. Even the most mundane quests (the "kill this"s and "retrieve that"s) are framed with some greater significance, giving the impression that your character is important to the story at large. The spoken dialog utilized throughout the game contributes hugely to this, giving the game a sort of "single player" feeling that one would expect from an RPG. Another impressive element of the open worlds is the companion characters. These companions again harken back to BioWare games such as the KOTOR series, and make the transition to SWTOR quite well. The affection system is quite well done, giving each decision a degree of weight, and it's helpful to build said characters to complement whatever role you're filling (i.e. bring a medic if you're running dps, etc.) The transition between planets is also nice, as it ensures that enemies stay more or less at the same level as the players, eliminating the possibility of stumbling across vastly higher-level enemies as is possible in other MMOs.
With all this being said, the PvE experience in SWTOR is far from perfect, and, in my opinion, often steps backward from Star Wars Galaxies, in many ways its predecessor. I'm intentionally emphasizing critiques here, since the positive aspects of SWTOR (and there are many) have undoubtedly been covered sufficiently across the web.
First, the combat. While the range of skill trees, specializations and abilities is nothing short of impressive, the combat itself is sorely lacking. The general mechanics are similar to other MMOs, but the vast majority of abilities, particularly for the trooper, are channeled, forcing the user to stand in place for four seconds after selecting an attack. To make matters worse, this immobile button spamming actually maximizes dps and power management, utterly discouraging any movement or variance. By the time I got 30 levels in with my first character, combat was a chore made worse by respawn times. Any time I'd enter a non-instanced quest area, I'd end up fighting the same npcs on the way out. In SWG, combat was not the torturous routine that SWTOR manages to make it. The actual damage mechanics were more or less the same (as with any MMO,) sure, but abilities lacked channel times, so combat quite frequently involved ducking around corners or rushing the enemy to get in melee range after your ability energy pool was exhausted. Any dynamism to the PvE combat is crushed by these stationary abilities. Also, the actual weapons you can equip are severely limited by class. You're a trooper and you want to use a vibroblade? Sorry, nope. You want to be a blaster-wielding Jedi? Too bad.
My main issue with SWTOR, however, stems from one of the previous positive points I mentioned: companions. To some, their very existence is problematic, as they go against the definition of an MMO: It's a multiplayer game. Yet, throughout my 50 level journey with my main character, never once did I feel compelled to gather a team to go through my quests; They were all perfectly doable with a companion serving as medic, effectively discouraging the one element that's supposed to make multiplayer games unique. Of course, this is far from the only cause. Many quests in the game have instanced areas, which only allow one member of a given class to enter at a time (each of the 8 classes has a different storyline, by the way.) As such, the only players who can help with class quests are from other classes. Players who have no incentive to help you since doing so won't advance their questline. In this way, I was actively dissuaded from teaming up on multiple occasions.
My final qualm pertains to the "end-game," where players are unceremoniously tossed from the storyline to the world of daily missions and instanced flashpoints. I'd previously mentioned that the entire stories makes players feel significant to the galaxy, and that is indeed true up to this point. Upon reaching level 50 and standing awkwardly in the Republic fleet (the central meeting place for high-level players,) I realized that I was surrounded by hundreds of identical troopers, each identically "crucial" to the same storyline. The singleplayer feel to the game that I'd enjoyed up to that point vaporized instantly, and my savior-of-the-galaxy trooper was just another face in a cast of thousands. To compare this back to Star Wars Galaxies, the storyline there did no such thing. In fact, throughout the story players were treated as just another rebel/imperial/freelancer going about their business. While some may dislike this approach, I feel it's more beneficial in MMOs, as it leaves players and groups to determine their own significance through their and their guilds' actions, rather than faking it then fading into anonymity. Real significance to the players, rather than feigned significance to npcs, if you will.
The guild system is another element of SWTOR which, in comparison to SWG, I found somewhat incomplete. It has all the basic amenities of guild systems in any game, standard fare like guild banks, inventories, messages, ranks, etc. But beyond that, there's very little substance. Even some sort of guild housing/meeting area would be nice for players to coordinate instances and PvP, though the existing setup does a decent job for larger groups. Coordinating operations for 10+ players can be next to impossible for smaller guilds.
My experience in PvP is somewhat limited, so I'll keep this short as well. There's a circulation of several maps centering on capturing and holding various command posts in a fairly standard fashion, a breach map, and a capture-the-flag-esque game called "Huttball" which is somewhat love-it-or-hate-it in nature. PvP in the level 10-49 bracket (all levels are scaled to the same stats) was entertaining, albeit somewhat laggy due to the number of players present. The combat is still somewhat slow-paced and stationary, but the significance of crowd control is much greater than in PvE, making things more interesting. The level 50 queues are barely recognizable when compared to the lower levels, and are substantially less fun for someone who does not enjoy competetive MMO PvP. Players without top-tier equipment (earned, incidentally, from winning in PvP) are instantly ripped to shreds in most matches. It could very well be fun for those with said equipment, but I'm not qualified to comment.
Finally, there's the whole free-to-play aspect of SWTOR. The game started out subscription-based before transitioning to F2P. As far as F2P goes, TOR actually has a pretty decent system. The perpetually-glowing Cartel Market (in-game store) button was hastily added to the top UI panel, and is somewhat annoying, but that's about the only reminder that the game is free in the PvE content. Sure, XP gain is slightly reduced and instance and PvP participation is limited, but I've played the game in free mode without any glaring deficiencies compared to when I subscribed. Also, the "pay-to-win" present in other games is largely absent here, as the vast majority of paid items are cosmetic.
As a whole, SWTOR is somewhat of a mixed bag, with some spectacular elements and some decidedly not-so-spectacular. The storylines (8 of them) are impressive, and live up to the expectations that come along with a BioWare game, and the graphics look great. The main deficiencies involve mechanics that dissuade collaboration/interaction with other players and limit combat options, and while these were highly disappointing to me when compared to SWG, others may find them just fine. In short, SWTOR is certainly worth giving a try, especially for those who enjoy MMOs with heavily story-driven content.