90% is the score for Mass Effect in RPG Fan's review, which starts by bizarrely suggesting readers go watch Yahtzee's Zero Punctuation review for a more succint version of the same opinion. Anyway, a snip on combat:
Speaking of Mass Effect's combat, it's done much better than either in Jade Empire or KoTOR. As you walk through the world, you can pull out your weapons at any time and go to town on anything in the environment. You have four weapons to choose from: a pistol, a shotgun, a sniper rifle, and an assault rifle. Each weapon is upgradeable to scores of other models and able to be outfitted with various modifications. The same goes for your armor, grenades, and any biotics (magic powers) and omnitools (hacker gear) you might have access to. In addition, based on your level in various skills, you unlock special abilities and powers that improve you and the things you can do with your items and armor. While it tended to feel a bit micromanagey at times, my biggest decision after a certain point was whether to use bullets that work better on synthetic organisms or fleshy ones. Major props to BioWare for avoiding the make-or-break micromanaging system from KoTOR.