I alternate between Northern Brewer and Midwest, both are out of Minneapolis so I get quick shipping to Iowa (and if you're inclined to think about things like this: minimizes carbon footprint). This translates into less worry about yeast problems for me. I am wary about getting stuff from MoreBeer and AHS just because they have to travel across some serious climate extremes to get to me, but I'm also moderately paranoid. My LHBS doesn't carry much, some DME, a few grains, and the most popular hops. I've bought from AHS before because of their huge selection of kits, but since I don't like brewing with LME, I've move away from kits. Otherwise, AHS answered my questions when I called them asking about yeast shipping in the middle of August from there to Iowa, and assured me they'd replace dead yeasties.