Gotchas in Analyzing Turnkey Properties

[Monte Riding]

I'm interested in a (remote) turnkey property as a first rental, and did my first analysis on some turnkey properties I came across today. The seller offered some quick financials that looked great at a glance, and all their properties appear to cash flow $200 to $400+ per month. After doing analysis on a couple of properties however, I quickly found that my assumptions didn't match up with the seller's. In digging further, it appears they are using really aggressive estimates on interest rate, PM, vacancy, maintenance, etc. On top of that.... the purchase price is well above what comps are going for by 20% or more. After using more realistic estimates, cash flow in most cases becomes flush or a bit negative. I was disappointed to find such misleading estimates being marketed to newbie RE investors.

What things should someone look out for as a first time investor in turnkey properties?