I was briefly in beta for Tabula Rasa and played a fair amount after release.  This is my quick and dirty review of the game from the perspective of a hardcore, 10 year, MMO Veteran/nut.  MMOs are all I play.

TR is a science-fiction themed MMO.  You're a soldier in an army fighting against an evil alien enemy that goes and destroys worlds (they destroyed Earth; you're one of the survivors).  We're now on another planet, fighting back against these evil arseholes. 

The gameworld and feel are quite unique.  The feeling of being in a war is very much in your face, and definitely succeeds.  You constantly feel in the middle of a war -- a very different feel in an MMO.  Graphics are very good, if you have the hardware (like any game).   Classes are well done, mostly.

The UI is very primitive.  Nothing is movable, mostly, and very little is resizable.  The developers had a concept in mind "just play the game and ignore the UI", which I suppose is great for newbies to the genre... but most vets are used to a lot of UI commonality between games, and without that... it's harder to get into.   Actual play is a hybrid of FPS style action with standard MMO combat, leaning more towards the FPS style.  You can use height and cover to your advantage (and the mobs try to do the same!).

There isn't much mob variety, at least not 1-35 or so.  There's the basic enemy (Thrax), some weird floating squid-like monsters (Miasmas), and some basic aggressive wildlife.  There are a few additions to the Bane army, but that's about it.  That is in fitting with the whole overall military/war theme, though.  I mean, you're fighting soliders in an enemy army...not gonna be much variation I suppose.

They don't seem to have emphasized gear much, and except for dyes, there isn't much in the way of ways to make yourself look unique.  Again...it fits with the military theme.  You're a soldier.  Would be nice to have some cool gear though, especially for gear fanatics like me. :)

There's no real crafting to speak of.  You can modify weapons and armor to add basic stats and that's about it.  I believe a "real" crafting system has been talked about.

Overall, the game's good, and has insane potential.  If they decide to standardize and improve the UI, and add a lot more content, especially at the endgame, it has a good future. :)