TSW's combat is GW1 style, only evolved, and with enough differences to not be a blatant ripoff - more of a homage. Same way GW1 was a homage to Magic: The Gathering.
You can equip 7 active skills, which you can pick from any skills you've already learned, and you can use them as long as you meet the weapon requirements, if any. 1 of those 7 active skills can be an elite. There are another 7 passive skills, which can also contain one elite, so they don't crowd your skillbar. Similar, to, but at the same time, very different from, allocating skill points in GW1 to make a build.
In terms of combat mobility, you can move while casting (at least, I think you can), double tap to dodge, see AoE rings, blah blah. Circle-strafe like mad when outmatched, stand still and hit buttons when your opponents are puny. At least, in melee. Not sure how ranged works yet.
Mobs don't seem to be as smart as GW1 mobs, but I'm a newbie still (a whole 3 days!), so maybe they get smarter later on. So far, though, they're still better than many other MMO mobs. They DO try to surround you (and hit your back). But they currently don't run from aoe automatically, don't rez each other, etc.
The skills themselves have a lot of interplay between them, but the kind of interplay seems less sophisticated than what GW1 had. There's no costly skills that make a lot of sense - e.g., Flesh of My Flesh, Infuse Health, not that many skills that promote team play above selfishness, e.g. splinter weapon, and protection is not as subtle and beautiful, e.g. Reversal of Fortune, Aegis, Aura of Faith. And there are no minion masters. *sob*
Setting
If you like Lovecraftian alternate-universe type stuff, TSW is great. It feels like a rich, solid, plausible, well-built world. The world feels like it has history. Of course, it's easier in their kind of modern alternate-universe-history setting than in a purely made-up world, as it's as simple as going, 'Oh ohtay, that's New York, and Kingsmouth is in Maine.' ;)
Writing & Voiceovers
The writing is just a notch under Witcher and Witcher 2.
The voice acting is superb, AND, like Witcher and Witcher 2, the animations are well done enough that cut-scenes feel like movies, like actual... acting, instead of a poor relation.
Pricing Model
It's on a buy-the-box ($30 or $60, you pick), then subscription-optional model. As far as I can tell, the cash shop is not rapacious or evil. There are a few (very few, well hidden) lottery boxes, so it doesn't seem like that's their main revenue push, and there's very little to no outright selling of power. Lots of selling of fripperies. And subs members get a 10% discount.
Fashion!
Fashion is great fun. Since your gear doesn't show as clothes, your clothes don't matter. Meaning you can wear anything you like! ;) And there's heaps of it in the Pangea shop in London. And of course, more in the cash shop. I love fashion cs fripperies. XD
TSW is the place where crazed build-tinkerers from GW1 should go. For peeps like that, GW2 is an utter travesty. TSW is... the game that GW2 should have been.