I have a new, (though, not new for this year), O-27 F type Santa Fe, with three passenger cars. This was a set that MTH sold several years back. The locomotive is more O-27 scale versus O. Especially when you see it right next to my AC6000.
Anyway, I ran her recently and I got to tell you, she was real smooth and very quiet. Not a peep or a problem. So, for me right now, that MTH locomotive best answers the question posed.
The 10th Anniversary PE set Berkshire is also real nice. It has a nice way about it and looks fabulous for a starter set locomotive.