Something is going to wear, so what do you want that to be, and how easily do you want to be to replace the worn part?
The 550 design wears the brass pinion, which is easily pressed out, and new one pressed in, and the hole reamed - easy.
Compare that to the traditional Rolex design - the axle is steel riding in a jewel. The axle wears and it is riveted to the rotor. You punch out the axle, which can distort the hole in the rotor if it doesn't shear off cleanly, causing the riveting of the new axle to sometimes be problematic. Axles come loose, causing the hole to wear even larger and winding to be poor - not difficult to do if everything is good, but the more you replace the axle the more likely you are that the entire rotor will need to be replaced.
Bearings - how friendly they are depends entirely on the execution...
2824 style - bearing is friction fitted and presses out and a new one presses in - easy.
2892 and Omega 1120 style - bearing is held in with a locking ring, so a tool unlocks the ring, new bearing is installed, the ring is locked in place - easy.
3301/3313 style - the bearing is not located in the rotor, but in the automatic winding bridge. When the bearing wears out it cannot be replaced, so an entire bridge needs to be replaced - $$
1150/1160/3330 series - the bearing is in the rotor, but is burnished in place - bearing is not sold separately so the entire rotor must be replaced - $$
New Rolex calibers with bearing - same as above and must replace the entire rotor - $$
Of the wat I'll call the vintage options, the Omega 550 style is the best IMO. It's easy to repair and doesn't risk you needing to replace the entire rotor because of the design. The Rolex style is much worse IMO.
Of the modern bearing styles, one where you can replace the bearing is ideal. The style where you cannot is IMO the worst of the bunch.
