I think we are forgetting one of the things that makes this rom so important. It's as close as you can come to a complete overhaul of the d1. Not just the UI, but everything. The devs for MIUI have taken droid 1 moding and gone in a direction that nobody has really successfully gone before, at least to my knowledge.
This is still in it's infancy. Now at this point in MIUI, I'm really only hanging with it because of the Dialer, SMS, Top-Bar Battery, and a few other random features. And I don't experience enough serious issues to move to a different rom. I've tried most of the roms on DF, and they all kind of blend together. Outside of a few features here and there, nothing really comes close to what MIUI has done and is still improving upon.
I never really understood the rom loyalty that a lot of people seem to have. The whole "you're with this rom or you're against" mentality doesn't really make sense to me and seems counterproductive.
The roms are more likely to improve when people are using it and reporting bugs, not when people experience bugs and move on. This goes for all roms, not just MIUI.