I chose this bike because I wanted a step through frame, internal hub and torque controlled center drive with a power pack battery motor system. I had a top tube bike and as I'm getting up in age, it was getting harder to swing my leg over the back of the bike when getting on. This was especially had if I was transporting a package on the back of my old bike. I wand an internal hub because I live in Chicago and a cassette was hard to manage with the frequent stops and starts city driving require. I wanted a center drive because it makes tire maintenance easier and the torque sensor provides a more natural feel. I chose the Bosh power pack over the power tube because it was really easy to find a rear rack bag the I could easily fit the power back into. An added benefit is that the shop I bought my bike from had several power pack 400 available because of upgrades to power pack 500 and were offering the 400 at a substantial discount. Bosh is also a brand that is known here in Chicago, a city that has not yet embraced e-bike technology. I really like my Primo Sport. I've had it for a week and already have over 150 miles on it. Its got a rear rack the accommodates both a rear rack bag and separate paniers, Is as quiet as a mouse and rides really well. It's a little pricey but In my 75 years I've learned you usually get what you pay for.