Mass Effect, like any Bioware game made in the last decade, is shit.

The first game was awesome because it set the stage for something amazing. It established a great premise even if the game itself was more limited in scope and shorter than I was hoping - I had expected more exploration and investigation. And of course the inventory system was horrible.
The second game brought some great environments and was longer, yet drifted too far into the shooter lane. You could also still see the marks where the core story had been repeatedly hacked up, culminating with a horrible final boss.
The third game just sucked, end to end.
A Fallout style game set in the ME universe would be amazing, especially if Obsidian did the story.