paint brands

If you are referring to Testors enamel, it usually takes a little longer to fully cure than, say, acrylic. If you mean that the paint is still wet or tacky after several days then it might be due to humidity in the air. Dry air will allow the paint to cure quicker than humid air. But even then it should be dry to the touch. When I use enamels...Testors or other brands....I can usually touch the model within the same day although I try not to handle it much until the paint is fully cured. As far as what paint is the best that is next to impossible to answer distinctly since paint choice is largely a personal preference. I use acrylic and enamel. As I said before, acrylic dries faster than enamel. But, acrylic also sticks better to a primed surface whereas enamel can be applied to bare plastic without any problem, usually. Most acrylics are water based which means you can clean your brush with water after use. Enamels require brush cleaner or thinner. Some guys prefer acrylics over enamels and some guys are the opposite. You'll just have to experiment to see which one you like best.

I assume you are using enamel paints. They do take longer to dry than Acrylics. Though days does sound rather a long time. I have found a day for enamels is usually enough to be touch dry.

Best paint is wide open to opinion. Some prefer Acrylics, some enamels and within that there are many ranges that people prefer for their own reasons. I prefer Enamels myself, using mainly Xtracolour. But many don't like enamels because of the smell, longer drying time and that are more hazardous than Acrylics.

Gloss enamel just takes that long to harden- it is the nature of the beast.  Industrially, heat is used to speed up the hardening.  I have made a heated drying box for Testors gloss enamel. I run it at about 105 degrees and it speeds up drying from several days to several hours.

Testors flats dry much faster- a few hours so I do not use the dryer for those.  If flats are still wet for days, you may be putting them on too thick.

Another thing you need to look at is your paint stirring. If the paint is not stirred thoroughly first, it does remain tacky much longer.

Just place a painted model inside a home-made dry booth (do a search at this forum) and any paints will cure in 24 hours.