I'm a real estate investor specializing in STR properties, a realtor, and I own a construction company.

Also, SAAS platforms are supposed to include support and service (that's the last S), but the quality varies greatly from company to company. 

I would look up NARPM and start with them..Below are some questions I would think would be a good starting point for you to see who really treats their company like a business or a hobby.

I'm working with a company who owns a small, 19 unit, senior and low income apartment building.

This company might be a good option one day, but not now. 

I used to own a large SFR management company I sold to Evernest in 2019 and I manage a Kroger SC and a set of retail condo suites for a client now but it isn't my thing. 

No issues as of yet and the property management company has been great so far.

I'm especially interested in hearing about how you've made a PMS geared more toward STRs work with MTR billing and leasing.I do remote operations support for an MTR/LTR company in Denver and am assisting with our tech stack build out. 

What I have been seeing by various syndication companies.1.

Quote from @Garrett Brown: Thank you, it is from a company called OOD for the mirror house and then everything else we build around it.