Joints are more popular because new potheads start on joints most of the time.And it takes them time to get to bongs.I was smoking for three years before I hit/got a bong. Bongs are way better IMHO joints and especially blunts taste terrible to me and bowls are alright and bubblers to but nothing beats a good bong.
Joints have a more widespread popularity. Just about every toker will partake in a joint every now and then. But I still know ppl who never touch bongs(for whatever reason, money maybe?)
It depends. If I have some mids I will smoke a blunt to give it some flavour. If I have slightly better weed, I roll joints. If I have dank I will rip bowls. It all depends on the quality of the bud.