Originally pros used heavy mono (20-30lb test) for flipping. When braid came along, alot of guys started to use it. Braid is more sensitive and thinner in diameter but now alot of pros and big bass hunters are going back to mono. Both have their positives and negatives, braid is stronger and more sensitive. it also has very little stretch and can pull giants out of the thick stuff. Mono is less visible has more stretch but a good thing is you can see and feel nicks and imperfections in the line so you can re-tie when needed. I have lost alot of bass flipping with braid because I didn't know that is was nicked or weakened. I use 1 rod with braid for pads, heavy cover, stained water and 1 rod with mono for docks, trees and clearer water. My fishing partner always uses braid and always does well. They both work, it's what you feel confident with.