SPR in London has RFID keys.

The only thing I see slowing transition is a combination of two things:

1) cost for hardware, software and installation coupled with
2) the prospect of very soon replacing this technology with smart phone keys and
3) whether the current RFID technology is forward compatible with what is/will be the smart phone solution

We'll see. Hardware will have to be updated for smart phone solution, and hotels sure don't want to undergo that expense twice in a very short period. From a business perspective it is very smart to wait at least until they know whether the RFID solution is compatible with the smart phone solution.