The_NinthWave

I went at the LBS yesterday. While they did not have an AC01 nor AC02, they had and AC AMP which is similar enough (apart from the 6000 C$ price tag) to at least assess the look, build quality and sit on it. They also had a Presidio 3 that I could pedal in circle inside the shop. I could not do more because this bike was already paid for and awaiting pickup and, it is winder so I was not allowed to try it outside.

I am as much, if else more confused than before since I can not really try any of these bikes and I have to rely on other's experience which I am still gathering here, mainly from Archwhorides whom I hope won't find me harassing .

Tire clearance
The AC01 comes stock with 28 but can accept up to 32.
The AC02 comes stock with 35, up to 38.
The Presidio 3 can accomodate at least 35 but no info on the website.
The Schwalbe Marathon Winter Plus (4 rows of studs), which I have on my actual beater, start at 35, so they won't fit on the AC01. I don't have experience with the Marathon Winter with only 2 rows of studs.

Anyone here can share their experience between 30c-2 studs vs 35c-4 studs ?

Alfine vs Nexus
I browsed the internet and yet, the info I found is still contradictory to my understanding. It is said that the internals of both IGH are the same but the difference lies in the way they handle disc brakes... This is confusing since the AC02 and the Presidio 3 both have disc brakes and an Nexus ??? There must be something else different that account for the fact that cheaper bikes have Nexus while higher end bikes have Alfine...

Any details that would shed light on my understanding of Nexus vs Alfine ?

Brakes
While both the AC01 and AC02 have MT500 brakes, the Presidio 3 has U300 for which there are no hits on Google, except for Marin... OEM brakes ?