Everything that can be said of the Hario V60 dripper for pour-over brewing can be said for the inexpensive plastic Bonmac version. It is based on the same principles except for the "swirly" ridges of the true V60 which some might argue have a function.

I would respond that if they do have a function, you could not discern it in a blind taste test. So swirly or not, you can try out the same principles as the V60 for less with a Bonmac. You will need a Hario kettle to get good results, because like the V60 this requires a controlled brewing technique.