Republic Wireless - Any practical experience?

The Moto X became available today on Republic Wireless. Can anyone speak to the service itself? I don't make a lot of calls, so I'm not terribly concerned with call quality (in fact, I currently carry around an old Nexus S that isn't even activated and just use it over wifi). My bigger question is how the wi-fi/radio switch works from a practical standpoint? Is it instantaneous? Can it happen mid-call/mid-download?

I'd be curious to hear any anecdotes from current customers.

Thanks, folks!