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 ?

per deal to do due diligence.. and IF they fund they say they credit you the 2 to 3k.... some people have gotten funding.. many others have complained on BP that they lost their 3k plus 1 or more 650s and the deals were never good enough in the eyes of DHM to fund them...

Try smaller community banks or credit unions.

I also have almost perfect credit.

They give you up to $5K credit, deliver the whole caboodle and you can have them set it up or do it yourself.