Institutional, Wall Street-er, if you will, here.
Mass market analysis is alright for a preliminary search to vet properties but scouring the market is arguably just as quick and effective once you get good at it.
Knowing how to search on Zillow or Realtor is already going to discredit 90%+ of places, then a two second look at a listing will discredit another 90%+, meaning the cream of the crop will rise in a matter of minutes, regardless of how you're searching when you equip yourself with the right tools.
Here's my beef with mass market: it's good but it misses things. Let's say the software uses the equivalent of Zillow's Zestimate to forecast rental revenue & expenses, they're off by ~10%+ - fine, it's a good start. It's not good enough to give investors important fundamentals: how CAPEX will affect IRR, terminal cap rates (TCR), area growth, crime, actual figures for vacancy, absorption, expenses, etc.
Not to mention that you're unequivocally not going to find every on- and off-market listing on mass market or a search engine like Mashvisor.
Tried and tested, my greatest deals have been found directly from the source in which they've been listed, with conviction and fast action. That said, there's value to be found everywhere! Happy hunting.