After 4.5 months and 2000 miles, the motor is still whisper quiet and the frame is rattle free. I really like the Bosch power pack battery it came with. The hole at the top make carrying it easy. I have an extra battery. It is small enough to easily fit into a standard size trunk bag. I can carry both batteries in one hand too. I did a 64 mile ride on one battery. I also like it has a chain not a belt. I have a bike with a belt and it a pain to get the tension and alignment right. I never hear any chain noise when I ride the bike.