Without doubt the Cytronex is the best electric bike I have ridden so far. It is great for fit cyclist who only need the motor to pull you up the hills but in standard fare 175 rpm motor it isn't particularly fast - just pulling to 14.5mph on the flat but much slower on any incline or headwind. I ride 20 miles a day and am no longer in my 20's so want more assistance (I am always tired!). I considered upgrading to the 190 rpm motor but (probably like you) I am quite hard on bikes, commuting day in day out. Even the 175 rpm motor gave problems with the freewheel so an upgrade to the 190 was out of the question.
One point I should make is that there are lots of happy Cytronex users so maybe I was unlucky. I have a lot of respect for the designs that Mark Searles has come up with but I wish he would put some of his innovation into designing a new motor!
So after riding such a great bike I am now in the position where I am in between bikes and there really isn't anything on the market that is 100% perfect for me with the posible exception of some of the Swiss Flyers (but way too expensive for me).
I'll have a look at the Panasonic range but in the past found them frustrating - great that they are good to cycle without power but then I found the power delivery odd (when combined to the 7 speed nexus hub gears). I think the way the Alfine works will make the bike a lot more pleasant to ride.
The Wisper is still on my list with the 906 Alpino which should be a good all rounder but I will have to wait for the test ride to see.