as living in the same area, I know your hills...the difference is like this
1 pie...take of at lights needs lower gears to be changed before stopping, steep hills need you to pedal in low gears with the motor, as by itself, you slow and slow and then fall sideways histerically in top gear in benny hill fashion, with a WTF look on your face ( especially like me if you purchased the kit at a reputable local UK dealer for considerable more ££££)...knees on the old fellas take a knocking, as whenever you really pedal, you tend to go hard pedalling at high torque at short notice with no conditioning, usually about 16-18mph......its strange, but you really do need to adopt a different cycling style, ..I found that I wanted to take over on flats for "fitness", however you usually take over at 20MPH plus, something I would never do on a normal bike...
2 pies.......WTF are my feet for.......hmm maybe I could amputate and fit ginger built home grenade lithium batteries in that space, rozzers would never know.....