I have a feeling that this port is going to translate really well. I'm pretty confident the coming XBLA version will match in quality and be very comparable in most aspects to the PC version.
I don't think that it will come down to one version being dramatically superior than the other, just some subtle differences.
I'm sure that the PC version will have more versatility with mods, and custom skins/texture packs, just because of the nature of the platform. We WILL however be getting these things for the Xbox after release, but it is not yet clear how this will be implemented. I'm sure they have to be very careful how they do this, in order to avoid potential abuses.
For the multiplayer side of things, I am looking forward to the XBLA version suiting my preferences more than the PC version by far. Why? I don't really care to be on a huge server with hundreds of other users, and I don't have the PC power to run my own private server for a small group of friends. I am optimistic that the XBLA version will be very user-friendly for playing with my XboxLIVE buddies in a griefer-free world just for us, built just the way we want. The Split-Screen Co-Op is already working fantastically smooth, and has piqued my GF's interest because of this feature!
I'm guessing that the Multiplayer will be drop-in/drop-out, with worlds shared through the new XboxLIVE Cloud drive, hopefully with some way to set permissions for access.