I played quite a bit over the weekend, and overall, I liked the experience but quite often I caught myself comparing it to GW2. The comparisons are not favorable to TSW, in nearly all but one case.
The GoodThe Setting - I really enjoy the setting. The mixture of Lovecraftian horror, modern times and myth make for a great setting full of potential for alot of cool themes, and from what I saw from the BWE, these are themes they intend to explore. The setting oozes atomsphere.
Characters - While a few really bad ones stand out in my mind, the majority of the characters are just fantastic, interesting and quirky.
Using your Damn Brain - I have admit, it was little jarring the first time I took an investigation mission and was required to solve a fairly (in hindsight) simple riddle to move on in the quest. But I loved it, and every other time I was required to do so. It's lovely and keeps you from falling into "Zombie MMO Player" mode.
Mixed Bag (Good and Bad) The Advancement System - While it's not entirely true what the Devs have said, that TSW has no levels. It does, but they're not traditional levels - they're item levels. So rather than raising a mechanical level, you're gathering better equipment. The method of advancement is different, but in the end it's the same effect. This isn't a bad thing, because they've set things up so that get AP and SP no matter what you're doing, so you never "out-level" content, and in a world with such rich lore as TSW, this allows you explore the secrets of the lowbie areas until you feel you're done.
However, the point of TSW advancement system was supposedly to give variety, but the limits on SP (which must be spent on weapons or other equipment in order to equip ever higher Quality Level equipment) neatly nips any variety in the bud. While playing, I was struggling to amass enough SP to equip the most powerful versions of my 2 main weapons and my talisman slots. This kept me from broadening my focus to other weapons and essentially locked me into those 2 weapon choices with no recourse - you can't respec SP. Now, while this pressure will eventually lessen in the endgame (as you are always gaining AP and SP, now and forever), it still sucks to be locked into 2 weapons when the devs are telling you how open-ended everything supposedly is.
The Graphics - A lot of the time, TSW looks amazing - I hardly even noticed the occasional low res object. But as one would expect from a Funcom game, the quality is very spotty, and the optimization is very poor. I found myself changing my video settings nearly constantly as one model or another would destroy my FPS, where it had been smooth as silk only a few hundred feet in the other direction.
Character Customization - I like what I saw, but I expect more variety. Not even options for height or build.
The Mission Structure - Save only for investigation missions, it tend to be very standard "go kill this, go click on this object" type stuff. However, I do enjoy those missions that require some brain power, and the characters or lore would often carry played out mechanics with atmosphere and interesting characters.
The Combat System - Speaking of played out mechanics....TSW exists sort of as a middle point between old, boring tab target combat and the high mobility fun of GW2. It's not bad. Usually, it's fun too, just....not as fun as GW2's.
The BadThe Business Model - Purchase + Subscription + Cash Shop?
forums.thesecretworld.com/showthread.php?t=20339 Utterly ridiculous. They're trying to get you both coming and going. GW2 has them beat handily with no monthly fee.
As Keinermacht mentioned, the "Meet Up" feature for jumping between instances of the main areas to meet party members is very frustrating to use, when it works at all.
All The Little Things I Used to Think Couldn't be Fixed - Or...All the ways GW2 has ruined me for every other MMO. Every time I had to fight another player to tag a monster for my kill counter quest, every time I had to wait for the monster I had to kill to respawn and a hundred other little MMO annoyances, I couldn't help but think to myself....I don't have to deal with this shit in GW2.
Estimated Mission Difficulty - Is Total BS. I had "Normal" difficulty missions kicking my ass, and was meanwhile breezing through "Very Hard" missions. Don't trust the mission difficulties. They lie.
Conclusion? Well, I really have mixed feelings on TSW, but overall I really enjoyed my time with it. Unless GW2 gets a release date (a close one) between now and release, TSW is going to be the MMO I play during the Summer Slump, until GW2 comes out. I know it sounds like I'm down on the game, but I did enjoy playing it.