Worth paying extra for carbon e-bike?

Go for the second from bottom, it has the full hydro disc brakes and the better groupset. As for carbon, don't bother. Also if you look on their website you can customise the paint job

I looked earlier in the year and there were 15% ish savings on last years model so worth a wait.

My friend got one orbea gain one from bottom at c.£2300 after a quadruple bypass and you really need to factor in the problem you're trying to solve. I wanted an ebike to commute and because i have circulation issues, I tried his (as he was selling). The assistance uphill is great but you pay for it massively elsewhere, even though it looks like a normal race bike. If you generally travel at >15mph on the flat with the Orbea it feels you are essentially riding with the rear brake on as the weight is in the back wheel. For him, unless we are doing a ridiculously hilly route (3,000ft of climbing or more) he's working harder on the Orbea. I'd imagine a carbon bike just means you hit the cut off quicker and the weight of the 2 heavy bits (battery and motor) are even more apparent.

So for my commute I went to the dark side an purchased an eMTB - the fat tyres mean i'm less concerned about potholes, have better grip for the winter and actually slow me down so the motor works more, I have though bought a naughty box for it to get more power out as you still found hitting 15.5mph too easy.  

Interesting thread this. I've not actually run into anyone with an e road bike what are they actually like?
For those with physical issues seems a great way of covering distance but are they much use to a relatively fast rider as they are limited to 17.5mph. I suppose the hills is where you'd make big gains.

The only advantage perceivably carbon would have over alu is comfort and that certainly isn't worth the extra £. My primary bike at the moment is a Caad and it is really comfortable even over 100+ miles I'm a convert back to Alu. I've managed to kill my Evo which is basically the same bike I miss it but not £1k much.

The weight differnce i can't see making any differnce, too battery life after all regardless of bike weight it will have a rider, either way it will be fairly heavy (road) bike.

8s cogs might be a bit gappy though with a motor could probably cope with a closer ratio cassette. cable disks on such a expensive bike, would personally smart.

Interesting the way people on here condemn Claris. My second bike, ridden a couple of times a year is Claris. My best bike is Ultegra RD8000. The rear derailleur on the Claris is a tad slower, but gives very precise, solid, changes, is easy to set up to run silently, and rarely needs adjustment. I find setting up the Ultegra to run silent across the range a constant faff. The Claris front derailleur is definitely a bit clunky though.

It is worth looking at the brakes on the cheap bike, as even an e bike needs brakes, and in my experience brakes are a target for cost cutting on cheap bikes. The unbranded rim brakes on my (Trek) second bike are useless, compared to my Ultegras.

None. Fit wider tyres if you want more comfort and save a big wedge of cash for something else!