There is a lot of discussion over chainless shaft drive vs traditional chain bike. To me, it is just a simple trade-off. You give up a few % of efficiency in exchange for less frequent maintenance and chain hassle free. Just google or wiki it, you will get the answers.
The fact is that there is no such good manufacturer who can produce quality chainless bike. Small manufacturers such as Dynamics make poor quality bike. Famous bike manufacturers with good production techniques and skills are reluctant to make chainless bikes, or just testing it a little by little.
I bought a Dynamics Sidekick 8 shaft drive bike in Feb 2010. Till now it is about half a year. Total mileage is about 2000km. All rides are on nicely paved roads and I am about 72 kg only. Last week, I was totally astonished by the poor bike quality. The bike frame was broken. It is a folding bike, but donít think that the breakage point is at the folding joint. The actual breakage point is at the bottom bracket which is the most unacceptable location to have frame breakage. You can estimate how poor their manufacturing work is.
Check the photos.
So, donít buy it.