Alan I have all of those.... Lionel F3s and F7s, MTH FTs and F3s, Atlas F7s and Sunset FP7s & F7s......
Best runners, smoothest, quiet, no jerkiness... without a doubt I prefer all powered Sunset single motor drive F units.
Out of the box looks .... Atlas and they run very well too
My Lionel and MTH F7s all get modified with details and run good.
My favorite set is the Sunset 3rd Rail ABBA set but they got a lot of modifications. I havent touched the Atlas set yet but I see those becoming a new favorite when I'm done with them.
I think it boils down to how much you want to spend for what you personally think is important.