There are vast opportunities for great trout fishing in both states, NJ and PA, and also NY. For me, it's all about location. What's the "closest" place to find my target catch? Am I after big stockies, or do I feel like hiking a wild stream? Maybe I feel like fighting some lake dwellers?
While it may suck to have to buy an out of state license, is it worth it in the long run to travel less and have more time to fish better waters?
I've fished a bunch of spots in NJ, PA, and NY. Had some awesome, and sh!tty days everywhere. All depends on how much time I have, what I feel like chasing that day, and my willingness to explore. "I could fish that same stretch I did well at last week..... but I kinda wanna check out this new spot?" The decision could decide whether or not I catch em up or get in a nice fishless hike......
As for quality and species of fish, it's been shown that ALL are available in each of the surrounding states. Just depends on what your after and how much time and effort you are willing to put into the chase.
All that being said, I have not heard about diseased stocked trout causing outbreaks in wild pops in surrounding states. Although I'm sure it may have happened and is not widely reported, I could see where it seems like an "overabundance" of caution to the fishing public. Keep in mind I am certainly no expert on the topic.
For me the only differ is, over the last few seasons, catching some decent size "stocked" brookies that were pretty unexpected.... Then again, one of my most memorable Bows, caught in an NJ river....
