I originally used it for the background and credit check feature and starting giving my tenants the ability to pay rent afterwords.

I have been rehabilitated my mother in laws house for the past three years, with the little bit of money I make, while fixing my credit from a mother that used my name in my younger years irresponsibly.

This strategy helps you (the investor, by getting land cheap) and it helps the owner of the land by geting out of a tax lien, protecting their credit, and they can make a few bucks in the process. 

Credit and background checks !

how can i evaluate the strength of my buyers offer besides the amount they want to pay...meaning can i ask to speak to their lender to see how tight their credit/DTI/bank statements are....last thing i would want is my buyer's loan falling thru two weeks before i close. 

Chase just sent me a credit score of 800 and a limited appraisal of 475k on my residence, which is owned free and clear.

If it helps to know, I have a $200k plus per year income, 750+ credit score and own two single family rentals already so I'm not a brand new investor.Any ideas greatly appreciated!

My credit is good, but I'd hate to see it take an unnecessary hit.

You wouldn't have it reassessed (that's for taxes) , you would get an appraisal, and if the property value is high enough to meet the banks criteria for Loan to Value, and your credit meets their standard, you should be able to refinance.

Looking for feedback on: http://www.rex-credit.com/ and  similar Loan Application sites ?  Are there any 3rd-party sites that review / rank such sites ?