So many TK's to chose from , whom to trust..?

[Steven Schreifels]

So I am new to Bigger Pockets community. Am I the only one confused as to the relationship between the different TC co's..? For instance here you can look at properties on Bigger Pockets site..but then on posts there's advertisments for Rent To Retirement, and AirDNA..then there is Norada. So I'm in process of doing research and getting my initial funds together. I have talked with a representative from Rent To Retirement and he was very professional, timely, and patient. However their site is lacking inventory (at least whats viewable prior to pre-approval). I inquired on a listing to find out it was sold. I then found another that initially looked good and when i did research on area (Adamsville, AL) found out has been losing population, income, etc. Meanwhile their website touts that they do market research etc to position you in great areas..must say i'm kind of scared. Is there a site that rates all of the TK's ? Just want to make sure going to be dealing with an honest and reputable outfit.