When you look at the prices xipi charge and then look at bikes from established brands you can see that technology like the Bosch system wins hands down for durability, weight, usability and reliability. You get so much more for your money from an established brand. When you spend over £2000 on a bike you don't want to be worrying about getting the motor wet! This is the UK so if these bikes are being sold in the UK they must be able to stand up to heavy rain, snow, ice, the lot.
It is farcical to spend this amount of money and then think "Oh, best not get it too wet".
If xipi used decent branded and reliable motors, this would be a start. The ones they use (or at least used to use) are just not up to the job for long term reliability and this matters.
My Bosch motor has been through it all and is as good as it was 10 months ago. The only thing I do is keep the transmission oiled, replace the chain before it wears, clean the bike once in a while, replace gear cables, disc brake pads, tyres etc. That's how it should be in my opinion.
Obviously home builds need more maintenance, but the point is, xipi bikes are sold as complete bikes so they should be more than capable of taking a pounding by the elements on a long term basis.
Each to their own and all that, but I would rather spend my £2K+ on a tried and tested design backed by the support you expect from a major manufacturer (and the support from Bosch is pretty good). At that price I really don't recommend investing in a bike which is effectively a kit bike built with bits that are just not good enough.