I had a chance to play with it this weekend and I'm definitely sticking with it for some uses. I was never able to rdp into an existing session (multimonitor or otherwise) but it works great for a secondary "rdp" or "remote" account for server management while the HTPC is in use. I'm debating moving MC to its own user account specifically for HTPC functions, which will allow me to muck with server processes on the secondary account while it's playing. I'll just have to keep using vnc to get into the HTPC session.
The other drawback I ran into was that I cannot seem to be able to log out of the remote RDP session once its been initiated. Therefore when I use my remote to shut down the HTPC from the main account it now asks me if I want to logoff the other users. I'll try to play with the settings some more.