I think ME2 is a great game, but i have yet to find a way to save everyone. After Legion is added to your party during the mission to activate the Omega-4 Relay, if you even do one mission, half of your kidnapped crew will die. Doing more than one will kill them all. Since Legion is added so late in the game, i've never cared enough to do his mission at the risk of letting half my crew die. This conundrum and the mining mini-game are the only flaws i see in this game.
ME1, though, has worse voice-acting, the textures take a long-ass time to catch up to whats happening, and it just doesn't have the epic-ness and the urgency of ME2. Also, i hate those goddamned fucking slow-ass elevator rides. Though ME2 doesn't really speed up the rides, they at least save some dignity by not totally failing at disguising their loading screens with them.
ME2 is better than ME1, but i still think ME1 is a great game.