Thunderbolt is AWESOME... and even more so because it is under an hour from my house!
I did lightning a couple of times last year and while it is cool with the banked corner, I like thunderbolt better because it is tighter/more technical. Alos, with the hawk you can do the whole track in 3rd and lay off at the end of the straight, or shift to 4th if you get a good drive...
I am doing Lightning on Friday with Team Pro Motion and I will be doing it again with Absolute Cycle on July 6th (monday after the long weekend...) If you have not checked out absolute cycle, they have great deals on trackdays. July 6th is $150 right now, but if it sells out, they will refund $25 to everyone! Plus they have free schools (intro & intermediate)
I don't really have much to compare NJ motorsports park to. The only other track I've been to is summit point (main). The NJ tracks are much smoother and facilities are much better then summit point. Only gripe is that they should have a hill somewhere to help unload bikes... Summit had a 3' berm that you could back your truck up to and make loading/unloading a one man job.
Let me know what dates you are planning on doing, I had 2 "spring" trackdays, 2 "summer" trackdays... I guess I need 2 "fall" trackdays too!!!