I have been traveling to and from the USA for over 50 years. I have had some good experiences with US Border Control and some really bad ones (for no discernable reason); the majority have been so-so. To me the biggest problem is the attitude of the staff - they are generally brusque, unsmiling and border on rude. You are not made to feel welcome at all. At the end of a long flight this is just another thing you don't need. Almost everyone I know who travels there regulalry has the same complaint and that includes a large number of US citizens.
It's not as bad as Russia but that's a low bar