Ok for US availability is very valid point. For Europe, where this Maxxis hype is pretty much same, availability is not that much of a question, as Schwalbe or Continental are as available as Maxxis if not more. Michelin, Vitoria or even Mitas is different thing, and you might have issues getting them everywhere. Another point is price, and again for US I understand you guys prefer Maxxis over Schwalbe or Conti, as I heard Schwalbe/Conti are super expensive over there, but here, they are actually cheaper then Maxxis.
@Erik Timmerman for me Maxxis line is actually quite confusing. You have 15 different models, and then inside of each model another 10 different options, from protection to rubber compound to I have no idea what, so picking right tire doesn't sound too easy for me. But on the other side, especially if you have several wheelsets for different conditions, such broad range, gives you more options to get best possible tire for certain conditions.