We used Lending Tree for a house we ended up not closing on. In my personal opinion, stay farrrrrrr away from Lending Tree... it seems to attract shadier mortgage brokers. I'm sure my experiences are somewhere here in the archive, if you're willing to search.
I am still bitter over the whole experience... we lost out on a 4 bedroom farmhouse with a HUGE barn, garage, other buildings, 114 acres, pond,... all for 90k on a foreclosure. Thanks, Lending Tree for referring me to someone who we ended up having to report to the state board of (whatever it is... governs banking institutions.)
2nd time around, a couple months later, we went with a local recommendation from our new realtor. I highly recommend going that route. We still had problems though... purchasing yet another foreclosure property, 30 days to close. 14 days before closing, our bank backed out because of a heating system issue. We got a recommended mortgage broker. It ended up costing us an extra 2k, but we got a better loan rate and terms; it'll more than pay for the broker in the long run.