Being with USAA for 40 some years, I assume I can comment.
When we bought the F250 we had a fat check book. however, Ford offered another 1000 off if you financed I think it was 10 grand with them. We were buying using ann X plan. After messing around with my stubby pencil for a nano second I jumped on that.
Made two payments and then wrote the big one for the remaining principal on the loan.
As a couple of others have mentioned, I thought that was a heck of a deal.
i don't think you will get hosed with USAA, but i would be hesitant to not get some kind of comparison before jumping.