whose bluetooth to rs-232 adapters to use?

Whose bluetooth to rs-232 adapters are worth using (and which should be
avoided?)

I'd like to find one that would support connecting to two different PCs, but
never at the same time.

I've got two laptops, one with an external usb adapter and the other with it
built into the mini-PCI slot (with WiFi). I'd never be using both PCs, it'd
be one or the other. How would the device providing the other end of the
serial connection handle switching between them?

Thanks,
-Bill Kearney