Haibike treking 9 - £3550
Basic fork but at least it is air not coil. Basic brakes, but for general use basic shimano disc should be fine- just watch out for micro leaks and replace any that start squealing soon after purchase.- That would be under warranty, take no nonsense off the shop, if theres any sort of a leak it will dramatically reduce breaking to pretty much zero and wont 'fix itself'
Other that that its pretty standardized, and unfortunately the level of kit you would find on a £750 non Ebike
Pluses - 625wh battery, so plenty of range - likely about 70 on eco, 38 on turbo.
Decent mid range spec gearing, that will last without any problems. Wheels while not great are adequate. 30mm rims, so you can fit wide tyres.
Built in lighting, mudguards and carrier, so pretty much ready to go and the only real downside i see is the sunpoor fork(but then im a confirmed suntour hater)
Focus Adventura 6.6- £3099
Very basic overall. Less specced brakes, smaller battery, average suntour fork, but again its air, which is lighter than coil, there its usually a case of 4 1/2lb Air - 6+lb Coil.Narrowish bars.
Not as good as the Haibike spec wise. I think things will need replacing sooner. Cheaper at 3100, and it shows in the build choice. Personally I'd exclude this one from your list.
Again built in lights, mudguards and rack
Bergamont E-Horizon sport - £2999
Heavier than the others, to much emphasis placed on 'E-bike component labeling' - this to me is a sign of its tat, they're hiding poor spec behind an 'E' label
Slightly better mid range gearing, better than on the focus but not the Haibike.
Larger 625wh battery which is always good.
Standard brakes and wheels, but a good quality rack and mudguards, i expect those will take the abuse of shopping. Again quite heavy for what it is. My full sus Scott is 23.3kg, this is 25.8kg
Scott SubSport E-ride-£3250
Heaviest bike in your range - 28kg - The coil fork is pushing that up, but still thats too heavy for what it is.
Remarkably you get a 4A charger, so full recharge should only take 4h. Better lighting system than any of the others,
Good level of Syncros kit(bars/stem/saddle etc) Wheels and brakes are on par with the others, low end but adequate for city riding.
Cube Kathmandu- £3200
X-fusion mig 32 fork - Aahhhggg avoid avoid - this is a poor fork, i've read too many reports of it being very problematic. Other than that its the same low end kit as found on the other bike, though the better mid range gearing, which is something that will take repeated use so its a plus point there at least.
Only a 2A charger which is a poor choice in my opinion, it makes for longer charge times. The others havent stated what their chargers are, i suspect they will also be 2A .Fairly ok with the mid range drive train, no probs there Weight 26.4kg - OUCH, thats pretty heavy.
Plus point for the suspension seatpost - comfy bum, always a plus point for a hardtail.
Nice colour of blue.
Personally I think its a bit of a flip up between the Haibike and the Scott. Maybe if the Scott had a better fork it would win overall.