I have a scale Hudson and I think it is fine. The valve gear and non-existant brake gear are definitely missed but they are beefy and run well. Some complain about slow speed operation and I haven't experienced any issues at any given speed. It will pull lots of scale cars with no problem. My Premier FEF is much nicer in overall detail and I can get parts for it, but it is over twice the price. So for the price point it's a decent scale loco.
As far as the 5205 and 5207 are concerned it appears that they were offered in two road numbers. This loco is prototypical for NYC, so I would imagine that two road numbers would be desired by NYC modelers.