It's a part 65-certified dispatch course, so it's perfectly fine for getting the certificate. I can't speak to the quality of Vaughn in general, although it kind of sounds like Riddle Northeast. I'm sure a Google search will turn up plenty of reviews or opinions of the college. As has been said many times here, the dispatch school doesn't matter. Just go to the one that's most convenient and/or economically viable for you.
Same story, doesn't matter. It's the same material taught at Vaughn, Sheffield, Jepp, IFOD, etc. with a different name slapped on the course completion certificate. Dispatch school doesn't even begin to touch on the tip of the dispatch iceberg. It doesn't matter if one school teaches it one way or another "exposes" you to JetPlan or something. Just browse the approved schools list for the most convenient option and get the certificate. Worry more about how you plan on studying at whichever school rather than what school you go to. If you go to any one of the schools on the FAA approved list and work hard, make the course priority #1, and go in with the mindset that you're there to learn, you'll do fine. No matter how your dispatch school does things, learning from the ground up about aviation operations, aircraft systems, weather, ATC, IFR, etc. is a drinking-from-the-firehose paradigm. Study smart, have the right mindset, and be ready for a lot of information. All that matters is the certificate, not the school.
I got my certificate there while obtaining my BA degree in 2011. The instructor was an old LH disptcher and knows his stuff. He also knew a lot of people in the dispatch industry. That said good luck in your choice.