I played all 3 games straight through earlier this year after the ME3 ending controversy broke out, and, while I enjoyed them all immensely, I feel that the first game is the strongest of the three, simply because it felt like a space adventure game. I mean, the uncharted worlds were simply just some random height maps that they threw some textures, a skybox and a couple of copypasta rooms on, but it still gave me a feeling of exploring the final frontier that the other two never delivered on, and in my opinion, they should have focus on delivering a more detailed and varied version of that rather than just scrapping it because the dudebros out there don't want to do things that aren't shooting people.
The first game probably has the most satisfying plot of the trilogy, with a much more optimistic and enjoyable tone, and it is probably the only game in the trilogy to deliver a satisfying ending. 2 and 3 whipped the first game's ass when it came to characters, though.
Also, fuck whoever decided taking the elevators out was a good idea. All that bitching seemed to really be directed at the long-ass load times, which are still there in the sequels, but with the elevators replaces with the stupid immersion breaking "Now Loading" screen that every other game uses.
I'm probably not going to double dip, but I do say that it is tempting, since it is suppose to run much better. If they have a patch that also restores all the little things from the ME1 sidequests that couldn't be included in PS3 ME2&3, then I might just bite.