I've read some older posts, but with the way technology is changing, I'm interested in what the best platform to handle hundreds of units for multiple owners is today. 

That is a long and deep answer that I could best summarize an answer with "technology."

We also have a healthy tech sector, with several broadcast technology companies located here.

Austin has seen the most significant population growth among the four cities, with an estimated population of 985,000 in 2019, up from 790,400 in 2010.Job market:Atlanta has a diverse economy, with strengths in several sectors, including technology, logistics, and media.

Take it for what it is worth, but over the past 10+ years I have been in real estate I have noticed one major flaw in this sector - the lack of technological advancement.

Generally, DSCR Lenders fall into three buckets:Traditional DSCR Lenders that do not lend on properties utilized as short term rentalsDSCR Lenders that lend on STR properties, however do so conservatively, either requiring the property to qualify as if it were utilized as a long-term rental; or require 12 full months of documented operating history on a STR platform.DSCR Lenders that fully embrace short term rentals, and underwrite utilizing cutting-edge technology tools such as revenue projections from leading data sources such as AirDNA, financing multi-unit STR properties (even 5+ units) and embracing seasonal vacation markets that don’t have traditional long-term rental markets.Rates have unfortunately ticked up lately - you are probably looking at something in the 8%-9% range if it only qualifies as a STR. 

One thing you may have missed is the impact of technology.

How good are they at configuration, design, technology, etc.

Plus with technology today, not really necessary.

Technology makes having an out of state accountant the same as a local accountant.