I borrowed my brother's Trek ebike (mountain bike) and cycled it up the Merry Harriers climb to see how it went. Climb is 1.3 miles average 8% or so and a bit of a slog in real life on a light carbon bike. On the (bloody heavy) mountain ebike it was a doddle, and I beat my best ever time easily, while keeping my heart rate below 130 bpm (just after a stroke), compared to well over 170 bpm on the normal bike. If I had been able to exert myself, I could have gone considerably faster!
My brother has ridden up 30% climbs on it, without too much trouble, when he could not get up them at all on a normal bike.
It has to be said, they are fantastic things, and allow you to put in just as much or as little effort as you like, so you can kill yourself up a steep climb, you just go much faster than normal.
I have ordered a proper road ebike (the new Giant Road E+1) but it is in a process of constant delays, and I am now being told it is not due until August (originally End Feb).
Geoff