Bit late to the party, but I'll report that I'm switching from Kinesis Advantage (dvorak layout) to regular computer and laptop keyboards (qwerty layout) without any problem at all. However, I took the time to fully master the Advantage and Dvorak, and then re-trained myself on regular keyboards and QWERTY.
If you plan to use the same layout on both an Advantage and a regular keyboard, it will be much easier, just keep using both types of keyboards regularly and you'll be fine. It's like buying a 2nd car, you need a few days to get used to it, but after that, if you regularly drive both, switching back and forth is totally natural and painless.