Credit Karma uses a Vantage scoring model (which we do not use in the mortgage industry), but the trend will be the same as mortgage scores. 

I would not characterize this as a scam per se.. but it appears to me to be a failed investment model..

Preforeclosure's best model is "going down with the ship". 

That is for you to model and assess.

I just used cash to build my first 3 specs no loans at all.. once done and sold then I went to lima got one loan from them.. then went to local bank ( much much cheaper) and got a 3 mil  guidance line and went on to build 30 or so in charleston.. you have to prove the model.. its not like buying a rental where lenders look strongly at your fico  fico is required but not the main consideration like and investor loan and all you need is 20% down or 30% down and a few bucks in reserve that wont fly with spec loans..

Transitions to different rental models?

 - recognize you are combining 2 if the highest effory rent models: student rental and rent by room. 

I've only been using them for a few months, but I like the model.

Once you find that company then you have to make sure that your business model aligns with theirs It is very important that you make sure you take the time to interview and have candid conversations with a PM company.

I can run and model numbers and am a CPA so comfortable with the finance side of things.