I would think that the cons are the fact that even if someone is upfront with you it does not mean they have access to the most competitive programs.
This probably becomes more apparent as you move away from a full documentation confomraing loan.
There are a lot of sub-prime bwrs out there who could have qualified for an FHA or CHAFA loan. If I were an upfront mortgage guy who did not have access to these prograams but provided the very best sub-prime loan that you could qualify for than you would have lost out.
If you are going to use lending tree for your loan you might be well served to get a costco card and participate in the rebate that goes along with using their program.
MOre than likely you are going to get routed back to Etrade.