I can only speak in regards to the USB UIRT transmitter... the MCE transciever (IRTrans based) that was embedded in my Zalman HD160 case, didn't work with LinuxMCE (it would recieve, but there was no way to transmit), so I disconnected it and added a USB UIRT. the install was painless and it detected the dongle completely, and when all was said and done, I added a Xantech double-emitter blaster cable out the back, attached them to my TV and cable box, and I was in business. :-D
you may have the same experience with the MCE dongle, not sure.
-Thom