I'm probably a little biased when it comes to this answer, however I've been installing TX controllers for years and I can tell you that once they are up and running (and any bugs are worked out) they run for a long time with minimal issues. I used to do alot of MCE but it seems they have their own issues anymore. I haven't installed any MCE in the past 5 years or so.
As far as proprietary stuff... just about any true Elevator tech can work on either one. Most issues can be figured out on a TX without having any special tooling. Usually we only need the Cadi/laptop to adjust the car in the beginning before turnover to the customer.