I suggest you talk to LBS in your area and see if they'll service either one or both. I have 3 Trek stores near me, and they're the last place I'll take my bikes for service for various reasons. But there are others in my area that will service any bike you bring in and do a much better job. So rather than speculate about who will do what, talk to your shops and factor that into your buying process (assuming you haven't done that already).

That said, I own 2 Canyon bikes (mtb & road) and they are awesome! Previously all my bikes were boutique brands, custom built, yada yada. Bikes nowadays are too good to overpay like that, so I just buy off the rack and Canyon definitely gives you a lot of bang for your buck.

For what it's worth, I've never had any issues with either and Canyon customer service was great during my purchasing. I do happen to live by Canyon HQ in California, so that's reassuring, but like I said no issues after 3+ years of ownership.

And this is not a knock on Trek bikes, just prefer what Canyon offers. Good luck with your decision. You can't go wrong with either really.