N-Scale allows for greater track-to-scenery, longer trains, more track in less space... etc... The disadvantages can come if you have trouble seeing things up close, because the equipment can be quite small... Almost everything that's available for HO is avaialble for N... you just need to be a bit more creative as to how you find it, or be prepared to do some conversion work. Most newer locomotives are easy to convert to DCC. Sound inside the locomotives is still in development, but no-doubt coming...
DCC PRR engines? What era? Most current lines from Atlas can be ordered with the decoder pre-installed... Any locomotive can be after-market wired for DCC as well... I took a quick look on one site and found a whole whack of N-Scale PRR diesels, many of which were already DCC equipped...