Handbuilt without a doubt. Ambrosio Excellence rims on whatever hub meets your budget.
Ambrosio are always stronger pound-for-pound vs Mavic.
I have a set of Excellights (the lighter version) on my winter bike, a set of Nemesis (super strong, the benchmark rim, but tubular only) on my CX bike and have run Excellence in the past. Great rims. Not as flashy loking as a set of factory builts, but generally lighter, stronger and more easily repaired.
No matter how I equip the rest of my bikes, I always use handbuilt wheels. They are completely bespoke, and the sum of the parts is usually better than the factory built alternative.