I've been riding one for 12 months now...
... and I can basically confirm the review points.
One thing they don't tell you is that you can fit a child seat to this bike, so myself and my toddler have been doing our commute of bike+train+bike. If you think 26kg is heavy, then add another 15kg of child. Whilst I can get the bike and him up and down the stairs at the stations, I find that taking the lift is preferable.
The 16mph and then sudden drag is annoying. I cycle in Oxford, and that includes the lovely Headington Hill and Morrell Ave rises. Whilst I was accustomed to doing around 20mph on my previous bike (Trek Soho Deluxe - belt drive + 7 speed internal hub gears - but stolen a year ago and replaced by this bike), the fact I can now dawdle at 15mph and arrive feeling fresh at work/home opposed to arriving drenched in sweat after a good workout is the compromise.
Note that the replacement parts are expensive though! The optional front suspension is over £200 extra. The computer the drives the motor costs £125 to replace, and does not like to be dropped. My first computer developed a fault without being dropped, and so I replaced it, only for the next one to be dislodged from it's mounting by a pothole 3 weeks later, smashing the screen. Back to the original computer, which unfortunately got dropped today, and another smashed screen. The bike's weight can be an issue if it is knocked over (and it is pretty damn stable, even on the train), but mine has been at least once, and that caused one of the hydraulic brake levers to snap it's mounting - if I pay Smart prices, that's another £180 replacement!
Yes, the pedals are damn slippy, especially in the wet, and definitely so with office shoes on.
Good points though - I started off by getting 60 miles per charge, though more recently I seem to be down to 45-50, and the last two bars of battery result in a noticeable lack of assist on hill climbs now. The battery has a 2 year warranty, but it's not very clear what standard they use to judge that - one part of the manual suggests it has to hold only 70% of it's rated charge to be considered fine. Doing around 8 miles a day (on average - I've done 1700 miles since I got the bike last year), I can charge the bike once a week typically, and that's simple enough to do overnight.
I'm fairly fit (and used to being one of the quickest off the lights and into the distance) so I can move the bike manually if the battery does go flat (or I'm feeling like I want some exercise), and I still power away from the lights more from my own effort than the motor (the torque sensor can't quite keep up), but yes, unless you want to push and maintain 20mph (which you can do on this - though the top gear feels too low for it). I am about to replace the rear tyre though, as I've pretty much worn it smooth, whereas the front one is still fine - likely due to the weight and distance (I'm 100kg + 15kg child + 26kg bike)
The regenerative braking is one of my favourite things about this bike - it provides a nice smooth slow down, ideal for city usage (assuming you're paying attention to what's up ahead), and because of the electric assist, you can get out of the mindset of needing to maintain momentum and not wanting to stop (as is all to common amongst my cycling peers), so it does make it more comfortable and convenient to follow the rules of the road. The belt drive is also something I can recommend highly - no more getting grease on clothes or needing to oil the chain and gears, etc.
I got this bike on a deal (ex-demo, mk I bike, which I upgraded to the latest spec by adding the remote control pack - it's the extra thumb control buttons) so even with the replacement parts and extras (smartphone holder), I'm still well under the RRP of £1800 and happy with that. The style is lovely (though not always easy to lock to railings and bike stands, etc), the lights are great, even on country lanes at night, and the range is good too.
As they point out though, this is horses for courses :-)