On-One tyres are hard to argue with at the price. Grip apparently isn’t on a par with something like a Bud in the mud/snow, but then a Bud is £95, floaters are £25, you pay’s yer money………
My On-One wheels have been Ok. Rear bearings feel a little rough after 600miles which is disappointing but not unexpected for cheaper hubs. There are at least 2 revisions of the O-O hubs so some differences might be expected.
The O-O rims are OK too, not lightest, but you can always drill them (I’m about to do mine, if anyone want’s to rent the holesaw, template etc). They’re a PITA to setup tubeless reliably, especially on the back. My front has been fine, but the extra side load on the rear unseats the bead. Solved with lots of electrical tape just inside the box section that makes up the bead seat to level off the rim a bit (adds about 40g per rim, but you take out 200g by drilling, and about the same again going tubeless).
X5 cranks have been fine. Only issue has been the drive side sticks out abit too far, like the axle is 5mm too long, or the frame 5mm too narrow (checked, it’s not). Which means the plastic top hat migrates out of the bearing, which makes the cranks wobble. Solution is to find a ziptie that fits the space snugly (I suppose you could wrap electrical tape round it to a 3-4mm depth and cut it off with a Stanley knife too, or find a spacer that fits).
If I was building it from scratch I’d probably use different wheels. They’re fine, but there’s enough niggling issue that I’d probably get chinese carbon rims and hope hubs next time (but that’s a £600+ wheelset, for marginal gains over a £200 wheelset).