There is some tire wear on friction drive, but not as much as some people state. Once you get used to them, & ride correctly learn to " feather " the acceleration, assist with pedals on hills & in the rain, they are fine. I can ride one for a LONG time on the same tire. Friction drives are the simplest to install & remove. Very handy when fixing a flat !! They usually come with a much better quality engine, compared to th Chinese ones , so much less time spent on repairs .
Chain drive, frame mounts do look better.