After a good 6 and a half hours with the Tera beta, I can safely say, its an MMO.
The combat is better then, say, World of Warcraft or SWTOR, where you only press buttons, introducing a more interactive experience by allowing the mapping of moves to the mouse buttons and having to aim your shots, but it has a very spammy feeling to it, where you find yourself hitting the left mouse button so many times you think you're going to get carpal tunnel. And from my time with the different classes, there wasn't that many different moves, maybe later on, but at low levels they all seemed to have the same kinds of moves, just they flashed different colors.
The quests are the usual "Go get me 18 bear arses" and you'll find yourself turning in a quest about killing ents, only to have a new one given to you where they want you to go get some ent claws, which of course means you have to kill more ents. The mobs are almost all the same throughout the area, just with a different tint and an adjective added to their names. This isn't new for MMOs, but seriously, you can't create more than 5 mobs for the starter area, the first thing everyone is going to see?
The graphics looked really nice and the character models looked really well done, though I'm not sure if it was a problem with my computer or the game, but there was some very clear texture pop-in on many occasions. The animations were strange sometimes, very fluid and solidly done, but the females ran with their arses in the air all the time and constantly moved their hips when in combat mode, I know this is intentional, but kind of off-putting.
And the clothes, oh the clothes, so very well crafted and put together, and so extremely revealing too. Have fun trying to find an outfit that didn't show off your female's underpants, and in the case of some of the more exotic species, had any sort of pants at all. I tried out most of the races, including the Baracka (big golem looking dudes) the Popori (fat little animal dudes) and the Aman ( reptile-dinosaur looking dudes) and many of their outfits had no pants at all, you could just see their crotch clear as day, sure there aren't any dangley bits, but once again, its very strange to look at.
All in all, it was a fairly average experiance for me, with some cool things, but many stale ones. The Beta isn't done until monday, so I'll keep playing a bit later, since I know that 6 hours isn't really a full MMO experiance, but for the most part, I think that Tera will get a farily big release audiance and then get forgotten by most, the way Rift and DCUO did, eventually going F2P in a year.
TL;DR: Spammy combat, generic quests, texture pop-in, hip swaying and pants-less outfits.