I think it's better to get a recommendation from some trusted referral sources for a good lender and just go with them. If they are very experienced and close lot's of loans, they should be able to tell you up front if they can close your loan or not.

It is a common request of some listing agents, as well as new home builders, that you "double-app", to make sure one is ready when the escrow needs to close.

The advantage to you, is that you can play one against the other - ala "Lending Tree", getting the best terms from one at close of escrow.

The only downside I see is possibly having to pay for two appraisals.

Personally, I would prefer that my clients get a lock from my preferred lender, whom I trust to come through as he's said he would do. He hasn't failed me yet - in a lot of years.

Good luck deciding, and buying.