I hope that anyone reading this post will jump in and add their comments!
The office where I used to work started out with the Tactile Image Enhancer (TIE) along with Flexipaper from Repro-Tronics Inc. They later moved to a high-end machine built in Japan by Matsumoto and purchased through JP Trading. It was very dependable, quick to process, and resulted in a high quality image (the results being also dependent on the quality (dark image) of the photocopier to which it was printed). They bought microcapsule paper from American Thermoform.
I'm looking forward to seeing more feedback with regard to what others are using!