Is Rocket Mortgage a rip off?

[Ernesto Cisneros]

Hello BP nation! I am a total newbie in the Southern Maryland area. I am looking to buy my first property and decided to go on lending tree to compare some mortgage companies. 

I am guessing I made a mistake, because now I get multiple calls a day from mostly three different lenders: Rocket Mortgage, Loan Depot and I am not sure what the third is.

They feel like salesmen, is there a catch with using them vs using a small bank or an established brick and mortar bank like BoA?