Whether its Lending Tree or any other Lender that you are not familiar with, Lenders that are not local to you or the property you are wanting to purchase, remember the old adage, "Buyer Beware". I have seen Lenders put my clients through so much red tape and make promises to them that my clients swallow hook line and sinker. Only when the HUD-1 Statement is presented to all parties the day before closing is when the REALTOR sees the fees associated with the Lender and by that time, the clients are already hooked, have their heart set on the home, and are ready to close, regardless of how much money they just got ripped off for. My opinion is just like every other professional that answered....stick local, stick with someone you know...or go to the Lender that someone has recommended them. In the long run, it is the best choice for everyone involved in the transaction. I have heard of those "internet" lenders pulling out at the closing table and / or filing bankrupt at the final hour and the seller, the buyer, the listing agent, the selling agent...and everyone that had a part in the transaction are left out in the cold.
Hope this helps!