First impression is that it's not as nice as my 6.9 Kg carbon bike, obviously at 18.5 Kg it feels a lot heavier and less precise, but comfy ride on 32mm road tyres (durano). In sport mode it picks up very quickly, but I could only ride around the car park today, I plan to try it up the Merry Harriers ASAP. Turning in the car park it felt very stable and handled nicely, should be fun on a downhill. Whips up to 25 kph very quickly, but then the assistance will quit so it's no advantage anywhere other than an incline, where a fit cyclist would drop below 15 mph.
To keep getting fit, I'd probably put it on minimum assistance and try and climb at the same rate as my friends, but keep my heart rate below 130-140. As I lose weight and get fitter and stronger, I should be able to do more on the normal road bike, whilst still keeping my heart rate down.
I did 20 miles on Sunday at an average around 12 mph, and enjoyed getting out, but my heart rate was hitting 150 as soon as I tried to make any power, so I had to back off all the time, and I'm still getting told off for doing to much, so a year or so on the assisted bike with a lower heart rate might be sensible.
My wife has suggested getting a couple of them in the future, and spending holidays riding around in the Alps on them, which sounds like a great idea. Go up at a pace that suits, admire the views and then whizz down again... sounds like a good way to spend your retirement!
Geoff