im an independent and only install non-proprietary equipment so i think im a little biased to be completely honest. i prefer non-proprietary just because i personally find it easier to work on - it depends on the manufacturer but usually there is no special tools required and if needed tech support is easy for anyone to get a hold of...so i would say MCE over TX but again thats mostly due to the fact I work on MCE and not TX...

That being said proprietary equipment does not necessarily mean trouble for you as a building manager - typically independent companies that are big enough will be able to purchase any special tools or software that is required for troubleshooting. they may have issues with tech support if needed since they are not affiliated with the company. Realistically though if the install is done correctly there shouldnt be many issues.

As i said i am an independent but i have many customers with proprietary equipment that i have been servicing for years.... the only concern i would say to be mindful of is the actual Schindler Tech that does the work - not all techs are the same but there are a few bad eggs (as there are in every company regardless) that could bug it in a way that makes your life more difficult at least the short term when a new company comes in to service it. Doesnt happen often but i have seen shady things like that happen before.