The Bethesda point is a fair one - they're more into the environment than character dynamics, which to me, is an opportunity missed on their part. It's great to go wandering around the different landscapes, but without rich character development and dynamics there's nothing really there for me long-term. Fallout 3 was a fantastic game, but once I'd finished it, I never really felt compelled to go back. ME, on the other hand, I go back to time, and time again.
Of course, the other RPGs to mention are the JRPGs, which I must admit, I adore at the times. I was a huge Final Fantasy fan long before ME ever came into being. There's no comparison these days though. Whilst JRPGs do feature romance and relationships between the different characters it's all pretty much railroaded. ME is far more intelligent and layered than that. Hopefully going forward they'll refine the system even further. I want to see more subtlety, a longer buildup, and relationships that truly operate in three dimensions. It was disappointing that the only recognition I got of my LI in ME3 from the other characters was from Javik, and that was it.
The romance and relationships side of ME is one of the key factors that sets it apart from other RPG series, and IMO, sets it above all the rest. I love Bethesda games, and I love JRPGs, but I'd take ME over any of them, any day of the week. Even despite some flaws in the wider game.