So I spend most of the last week evenings and an incredible "I have no life, I am a geek."-weekend on Mass Effect 1&2. I know I am late to the party. Obviously I am through with 1, and I think I am at least in the last third of the second game. I yet have to complete three loyalty missions and then await the installation of the reaper IFF. I am happy that I continuously played this on the 360, so I could transfer my safe file. I own ME1 for PC, and there was the option of playing the second on the PS3, which probably would have saved me quite a bit of money on the DLC (got all story DLC), but at the end of the day would have sucked to use a predetermined backstory in 2.  
 
The way I play RPGs (good guy, always get the 'charisma/persuasion' stat up as high and soon as possible) a playthrough evolved, that might not be possible with the comic In the QuickLook video. Most notably I talked Wrex into trusting me. I am not happy with how Ashley was handled. I got flirty with her, but we never kissed, and I politely turned her down before Ilos. My Shepard really did not dig her being a xenophobic space redneck. But in ME2 her picture was on the table and the whole scene on Horizon was (probably) as if we would have a "full relationship". I am currently with Miranda.
 
I will continue with this save in ME3, to have a "natural playthrough", but I see myself playing through all games again so I can get the outcome/romance that suits my ridiculously nice Shepard, including a Happy End and him being completely faithful the whole adventure through.. (If they do not employ the "Protagonist sacrifices himself in final mission" plot element. Which is overused IMHO.) 
 
I might try "Insane" on all of them, at some point, but I am not sure if it is feasible with a class other than soldier. The controls and generally the combat in ME1 were terrible. But I played on normal and set powers to active. After some upgrades Wrex and Tally were doing most of the killing. Including the final boss. I doubt you can do this with a Shepard that is as sturdy as the Soldier. And on the other hand: In ME2 I am doing most of the killing, I am not sure if other classes have the firepower e.g. against heavy mechs.