my question is, does anyone have a certain type of paintbrush they use for painting on cakes? Natural, synthetic, etc. etc. . I'm just curious if one would work better than the other types.
Either will work just fine. It becomes a matter of personal preference for type & price. I like a natural hair brush with a plastic handle [no peeling paint] that isn't too expensive. I use different shapes for different applications.
Just make sure that whatever you use it's good quality that won't drop hairs onto your cakes. I just did a video on youtube about painting on fondant and that was one of the things I was thinking about...I once did a car cake and realized that my brush was dropping tiny hairs onto the car as I was painting it. I had to go pick them all off, which was annoying.