-
A, why wouldn't you, if you know one end of a spanner from the other? Can't remember if I've ever even seen a cartridge bearing hub with adjustable preload and angular contact. They often have crap sealing too.
ii) Shimano are the only ones aside from cheap copies like Alex and Joytech who make proper freehubs which employ the cassette body as a stressed member to put the drive side axle bearing where it belongs.
3, Shimano is like Giant or Toyota; a huge company with engineering resources to burn. They invented almost every major improvement to road bikes in the last forty years, and continue to kick arse.
Since Shimano have finally brought out some rims in a modern width, the answer to what wheels you should buy probably just got a whole lot simpler, unless you want full weenie spec.
For real world kit that's better engineered than anything else, now it's Shimano hands down.