I played the whole trilogy with all the DLCs on the PC a few years ago. Last winter I got all of them on the PS3 as well (sans some DLCs which I didn't care for much) and am in process of replaying.
ME1: as a game it kinda sucks but as a sci-fi epic, it's grandiose. I think when I say 'those 2 moments', you'll know what I mean. Sometimes I just look up those 2 scenes on youtube and watch them a few times, they were so strong. And the thing with Wrex was tense too.
Overall, a truly grand experience, unfortunately BW really didn't know how to wrap a half-decent game around it. And the first few hours in the beginning is probably the slowest start to any game this side of JRPGs.
BTW the way I dealt with the combat was using the sniper role and setting the difficulty to easy. It's still somewhat challenging to actually score a hit while your accuracy sucks, but at least you can kill something. And instead of a terrible shooter you get a fairly decent sniping game, with the pistol actually being pretty good for close combat.
ME2: Sorry, but for me this is a complete piece of garbage that pissed all over what ME achieved. It almost made me sick to the stomach how EA-ified this thing is. As I said, I'm replaying the games on PS3 and already finished ME1 - and I really, REALLY don't want to play this tosh. If only I could transfer my save from 1 to 3 directly I'd be happy.
ME3: Here's a funny thing, I played this game long after it came out, with all the DLCs included. And I absolutely loved it, including the ending. It was fairly well foreshadowed after all (again in the DLCs). It brought back the best from ME1 and improved upon it and closed up the story in a way which, isn't cheesy. The ending that was originally intended and leaked, also hinted in ME2 (another example how ME2 pissed all over ME1), would disappoint me greatly or perhaps send me into a rage.
If you don't know what I mean:
What I loved even more is the feeling of war. It's not very often that games depict an utopia which becomes a shelter for refugees later. And ME3 completely nailed it, exactly in the way a sci-fi epic should.
That said, I fully understand that if someone played vanilla ME3 after it came out, it must have been a complete letdown, especially combined with EA's abhorrent DLC practices. But the game, yea the game is great, somewhere in my top 10.