The Wyse terminal is a smart design choice. These older desktop / terminal systems have plenty of power to run a specialized software package, and they tend to last way longer than the manufacturer intended.
I have an FT-891 and I noticed I have to jack my mic gain way up to get any output on the radio. I am considering a Heil headset. I generally use apple ear pods to listen to the radio, so the experience might not be all that different. Anyway, I noticed there is an 2 different microphone offerings. Which one should I go with?