I hated this game. It felt so much like an action game made by people with no understanding in how to make an action game. Cover system was bad and level design was not adequate for a cover shooter (oftentimes you are attacked in long, featureless hallways with nothing to hide behind).
The game loves to throw pointless cutscenes at you that end up ruining the gameplay. For example, you come to a clearing, then a cutscene shows a group of enemies approaching, and when the cutscene is over you're out in the open, already getting battered! No matter how you approach that clearing, as soon as that cutscene triggers you're back out in the open and screwed. (I'm speaking specifically of the mining planet where you find Liara here)
The AI is terrible, content to charge at you and fire recklessly... which seems to work out for the enemy, but notsomuch for you. The whole point of a cover-based shooter is that both sides keep a distance from one another! Teammates are the real problem, though. They need to be babysat, but you are given neither the vantage point nor the level of control necessary. They are useless for flanking and providing covering fire, which is just about the only two things that they can do.
The RPG bits fail to convince with a very limited amount of sidequests that amount to things like "Find all the bugs in the citadel" and typically Bioware good, neutral, evil dialogue trees.
It's not so much an RPG as it is a bad shooter where you can make fairly meaningless dialogue choices now and then and with limited stats you can raise. So it's about as much of an RPG as No One Lives Forever 2.
I would say that the graphics make up for at least some of its flaws, but with the glitchy shadows in the PC version and the heavy UE3 jaggy aliasing... eh, notsomuch.