Jonathan,
Based on your buying preferences, I assume the A5 you will buy will be a Sunset/3rd Rail model. I have the oversize K-Line/Lionel model, but wanted a scale model of it. I was looking at 3rd Rail's 3-rail version of it, but after talking to a few folks who do command upgrades, it sounded like this little brass engine would be tough to upgrade. I finally settled on the more scale sized MTH model.
Ron,
I'm not necessarily set on a Sunset A5, just a 2 rail one since all but two of my PRR steam locomotives are 2 rail. I honestly haven't done much research on even who makes that model in 2 rail. I know GEM imported a fairly average B6 that can be found fairly reasonably priced at times, but as I've found with the F3 Mogul, you get what you pay for on those even though mine is a later one with a can motor.
As for the J1 in 3 rail, it seems that you can't go wrong with any of the major manufacturer's versions. As for mine, it really is a fish out of water as it never got close to operating on the eastern seaboard, but I really don't care. I like the locomotive's lines quite a bit. If I ever need to pull a 50 car commuter train, that will be my go to locomotive.
When I get some time, I'll need to photograph my other Sunset steam locomotive that I have not posted here which is an M1a. A really nice model that lives sadly in a box too much!