Older homes will typically have systems that are out of date - even if only partially. 

Stessa is really an awesome system.

Also, how much does it cost to get set up on this patented software system?

In our student houses we use a programmable thermostat, but our building monitoring system has its own sensors and can override the wall thermostat and will not allow the temperature to get below 10C (50F) ... we are presently testing a new software load that will also prevent them from cooling the house too far in the summer.

It’s as if pointing out any negatives about the guru, or his system, is a personal attack on themselves.  

. - Your portfolio will suffer:(You want a PMC that has great systems in place, including a great portal where you can keep tabs on eveything.You will also need to manage your PMC on a regular basis.

For many, their downfall (and really what makes it so easy) is that it is a single-entry system. 

However if you have enough reserves, 6mo or greater then I'd say chance it but a couple of missed payments from the tenants and you have to foot the payments out of your own pocket.I'm all for taking risks but I think you really need to evaluate the age of the major systems so you don't get hit with a bunch of cap ex all at once as well as your reserves. 

Overcrowding can strain plumbing, electrical systems, and air conditioning, leading to expensive maintenance issues.

I strongly advise anyone purchasing an old house to flip to ensure they have a clear understanding of the condition of the home's drainage system.