For what it's worth, I got a new MOgul on Thursday and replaced it today at a Sprint store (up on the Dpad wasn't working). It came with the new ROM, and I didn't even realize it till I saw this new thread. I didn't notice anything different per-se, but the Sprint music store IS working, although it used to say coming soon - I assume that means it's here now.
One thing to note - the home page on my device doesn't work. I get an error page when I first open IE (a 404 page on the Sprint website). Maybe that'll get fixed later too.
The Sprint store UI seems to be crap though. I can't seem to use the stylus to move between fields or scroll - like it's designed for a phone with a Dpad only.