The B&O is my second one, yet to be stripped, the unlettered is the first. The unlettered are hard to find. The closest prototype locomotive I could find was a Baldwin built B&O Class M-60/68 of 1893, most 4-4-0's have a wagon top boiler.
I think the locomotive is great, I base that on performance, appearance is secondary. I have had several brass locos that looked great but were lousy runners, or the Bachmann ten-wheeler that won't pull it's on weight. It runs perfectly around the dirty track and electronically challenged Atlas turnouts of the Pacific Coast Air Line Railway.
It has traction tires on the front drivers and picks up electric on all the tender wheels and the back drivers. Mine pulled a train of 3 On30 Bachmann Passenger cars and 18 On30 Bachmann freight cars, I don't have enough knuckle coupler equipped HO cars.
The locomotive runs well on DCC and DC. The sounds are good for an HO locomotive, but that is subjective. I benchmark that against my On30 locos with a Soundtraxx Tsunami and two 1-1/2 speakers. A seperate controller operateds the DC sounds. There are enough chuffs and whistles to find one that is plesant.
The appearance is retooled MDC. The details on the boiler are seperate so it can be detailed without any problem. I find the detailing good.
I really like the locomotive and run it as much as I can.
I don't model the SP so I don't know if it matches any of their 4-4-0's.
Just a thought
Harold
P.S. Don't try to get one from RC Planes and Trains on e-bay, I had to go through Paypal to get a refund. First Hobby has the best price.