When I toyed with the idea of a mortgage, I used this site. I filled out the required information and sent it to them. I did not see an inquiry hit my CR from that information.
I received several calls within 48 hours, and I talked to several lenders. Here is where it went bad, I told them that I was not interested in a mortgage now. I wanted to just see different option and such. I gave my information to them, but I repeated that I did not want a mortgage now.
Guess what? 3 lenders pulled my CR, even though I specifically told them I did not want to get a mortgage now.
I think they are a fairly good option, but just make sure you are 100% ready to get the mortgage now.
Personally though, I think your local credit unions will probably beat the rates you can get on Lending Tree. If you do not mind me asking, what are your scores?