You'll read online that the x35 emotion hub motor may not be powerful enough. For me it's perfect because it provides enough assist to make every ride enjoyable again. Level 1 is like a gentle tailwind and makes those "out and back" rides perfect. I use level 2 for considerable assistance on long or steep climbs like the Blue Ridge Parkway. Can't tell much difference in L2 and L3 so I never use it because I figure it's just more drain on the battery level. I think that changing a flat tire on a ride like I was accustomed to would be a nightmare on a rear hub bike, so I added tire liners.