I have a friend in his mid-70s who is still quite
a
strong road rider. He also has an e-mountain bike that he rides both around here (MI) and at his place in Colorado. He really enjoys it. Not sure on the brand but it is probably a good one - I would suggest checking out what is available at your LBS. Having good tech support may be more critical for an e-bike than for purely mechanical bikes.
Interesting to see this thread come up again. I wouldn't change what I wrote 10 years ago....
Any bike I am riding at the time is the best. There is no bad ride.