Tough question, but I'll give you my pros and cons
cheap to maintain, insurance, easy to work on, excellent gas mileage, parts are cheap, light, easy to handle, cheap to modify.
enough power to get into trouble, not enough power to get out of trouble.
I've owned big bore bikes, and small bore, and the advantages of a small bore ninja is the handling, especially once you get set up for yourself.
I now currently own a 91 EX500, and 98 ninja 250, both I'm happy with, I took the ninja 250 on a road trip about 2,000 miles and not any issues whatsoever.
Hope this helps, and here's some reading material for you,