i knew nothing at all about motors, or how they worked when i got my first kit. i straight winged it!lol(and it went well)
if you can read, use common sense and having the right tools helps. i think almost anyone can install a china kit on a bike.
i have alot of fun on my bike. iv bought 3 kits total, and used one to build my friend a bike. i think i can speak for him here and say, he enjoys his bike alot more with a motor on it.. if you have the know how already, and a bike. whats the $200 to give it a try,right??
they are, for the most part cheep to fix. and if you know what your doing, can fix most to all problems yourself. you can install them in under 10hours. even take your time to do it all right. and all the aftermarket parts are really nice. makes it easy to adapt your bike to where you are riding.