@CH19830 Good that you got hands on them in person, that's worth more than any spec sheet I can pull up.
The flexible battery and drivetrain covers on the Cube are a common observation and honestly a bit of a letdown on otherwise well-specced bikes. They're functional but don't inspire confidence, especially next to something like Trek's Motor Armor and integrated frame protection which feels considerably more robust. It's a cosmetic and durability thing rather than a structural concern, but I understand the impression it leaves.
Now, the Rail+ is a genuinely different proposition to what we originally discussed. The Gen 5 Rail+ features a completely redesigned frame with the Bosch CX Gen 5 motor and 800Wh battery.
It runs a mullet wheel setup (29" front, 27.5" rear) with 160mm of travel front and rear, so this is a proper enduro-focused machine. That's more travel than the Cube One44's 150/140mm setup, and the mullet configuration gives you a bit more agility at the rear end, which is handy on tighter Peak District singletrack.
The Rail+ 5 at £3,400 is cracking value if that's a genuine deal. The 2026 model retails at £4,250 at Trek Store, so that's a healthy saving. At that price you're getting RockShox Psylo Gold RC fork (160mm), RockShox Deluxe Select+ rear shock, Shimano Deore 12-speed, and Shimano 4-piston brakes on an alloy frame. The spec is a step below the Cube on component tier (Deore vs XT, Shimano brakes vs Fox suspension), but the frame itself and the overall platform are excellent.
The Rail+ 8 at £4,100 is where things get interesting. That gets you a RockShox ZEB Select fork (38mm stanchions, 160mm), upgraded shock, and Shimano XT 12-speed drivetrain.
The jump from Psylo to ZEB is significant: thicker stanchions mean stiffer, more controlled fork, and XT is a noticeably nicer drivetrain than Deore. For the Peak District, where you'll be hammering through gritstone chunder in the wet, that beefier fork is worth having.
On the warranty point, you're right that Trek offer lifetime frame and wheels, plus 2 years on parts, suspension linkage, and paint.
That's genuinely industry-leading and a real consideration for a first bike purchase. They also offer a 30-day unconditional guarantee in case you decide the bike isn't for you, which takes some of the anxiety out of dropping this kind of money.
The one caveat worth mentioning: Trek have a MinoLink geometry FlipChip that adjusts the head angle, seat angle, and BB height, with the head angle sitting at either 64.5° or 65° depending on the setting.
That's a nice feature for dialling the bike into your riding as you gain confidence. The adjustable suspension progression is a bonus you won't find on the Cube too.
Long-term reliability wise,
@irie has put over 4,000 miles on a January 2022 Trek Rail 5 without major issues other than a rear wheel rebuilt under warranty. The Bosch CX motor is well proven at this point.
Between the three, if the Rail+ 8 is genuinely coming in under the Cube One44 price, I'd be hard pressed not to take it. You get the ZEB fork, XT drivetrain, 160/160mm travel, 800Wh battery, lifetime warranty, and Trek's build quality at a price that undercuts a bike with arguably lesser frame protection. The Rail+ 5 at £3,400 is also phenomenal value if budget is the priority, you'd just want to factor in that the fork and drivetrain are a tier below.