I have both an Athearn (MDC) RS-3, and an Atlas Classic Series RS-3, both in B&M schemes.
The Atlas is definately a better runner, espescially at slower speeds, but was not DCC ready so I had to wire in decoder. I used an MRC 1650 (let’s not get started on that, a handful were given to me free when I first made the jump to DCC, when it dies, I’ll replace it).
The Athearn came DCC ready with a JST connector, I removed the dummy plug and installed a Digitrax DH123. The only issue I had with the Athearn was removing the shell. It seemed to be more of a struggle than it should have, and the handrails are definately more delicate than those on some of my other models.
In the end, the Athearn was a good investment, I would get another, especially for the cost and the Athearn being DCC ready.
I have 2 of the new Athearn RTR RS-3’s and 4 of the older Atlas “Classic” RS-3’s, All in Boston & Maine.
Here is my 2 Cents on both of these models.
The New Athearn RTR looks nicer. It has the correct horns and steam stack next to the cab. Under the shell, it is DCC ready. I have installed DH123’s in both. In DCC however, they do NOT run as well, or as quietly at the Atlas units.
The older Atlas “classic” RS-3’s run better than the Athearn RTR versions. The drives are almost bullet proof. They are NOT however DCC ready. You have to remove the existing pc board and install your decoder. I’ve installed DH163AO’s as well as golden white LED’s. The shell is not up to par with the Athearn RTR version. The horns are in the wrong place and there is no steam smoke stack up next to the cab.