Hi chloemac,

I would prefer gelcoat only, because I think that it is easier to make repairs on a gelcoat surface than on a gelcoat (polyester) + paint. But I never repaired a painted boat, so that's maybe my lack of expierence.
There are basically two sorts of paint:
acryl based
polyurethan based (PU)
Acryl is what most car builder use, PU is a high quality paint which is used for aircraft for example. Some boatbuilder use it too (good against UV rays, most solvents, chemicals, etc.). But its solvent is highly toxic.
If you want to make the paint work by yourself, better chose acryl based paint, which has still good properties.

Cheers,

Klaus