With painting, you get what you pay for. Spray painting it yourself can turn out good but it really depends on your prep and skill with the paint.
I guess the most important thing is, don't leave your fiberglass without some kind of protectant coating. If you strip it Prime/Paint it as soon as possible.
If you prep and tape it yourself body shops ussually wont charge you an arm and leg to paint it.
The absolute best thing you can do for longevity is to strip the top completely, then get it primed with 2k Epoxy Primer which will seal it, then paint.
Oh and if you decide to strip it using chemicals, be sure to use a fiberglass stripper, regular autmotive paint stripper will eat through the fiberglass.