I don't want to answer about mac vs pc but I would check to make sure that the EXACT equipment you are using is supported directly by either or both software companies.
I know for sure that there are problems with Shinko 2145 and with some new cameras. The software needs the SDK's for all new devices to write directly and some equipment mfgs are months getting these out after the equipment is already in use. Workarounds are NOT acceptable. ie: using the Shinko as a generic printer vs. direct drivers.
ED just released a new version with much improved green screen capabilities as of last week. You can download for free trial. The very few people I have heard about that run both seem to prefer TEPS on site on a mac and ED in studio on a pc. There are only 2 people that I have ever heard of doing it. If you want further info, you should join the users groups and ask there. ED is at
ExpressDigital : Digital Photography Solutions Software and Equipment Discussion A decade ago I made the same choice and went with ED because there were a few problems with TEPS that were deal breakers. I have no idea what has changed on TEPS since then.
Doug
OOPS - I just noticed your post on ED for the same info. Read the last few weeks of posts and do a search and you'll get a better answer.