I had the double chainring on my old Hard9.
Can honestly say I never felt the need to drop onto the other ring and I ride up some pretty steep climbs!
I've got the Bosch now on my UrbanRC and it tackles everything really well.
Have a look at the Capital to Coast ride. I marshall it every year on the motorbike.
Really lovely routes and normally up to about 1500 cyclists as opposed to the tens of thousands doing the BHF ride.
E-bikes no problem either!!!