Yeah MIUI for the D2/DX is a fairly new deal, it came after 2nd-init did.
If you mean the newest version which I believe normally comes out on Fridays (I didnt check to see if it did) I am sure quite a few people already have. Its become very popular very fast, especially since its so new and so different from the other choices we have.
I have a feeling this is whats holding up some of the ROMs from being updated as quickly. Not to say its why MIUI missed the last couple but many devs are working on this, either to perfec pr make the transition. It will be to our benefit.
Of course I have been wrong in the past so who knows...