These are dangerous waters because we all have different palates. For instance, Barn Town IPA's, to me, are very juicy, like overly juicy. They also use lactose in a lot of their beers (allergy), and all of their sours seem to be "pastry". That doesn't mean I'm wrong when I say they're not good, I just don't care for them, so rankings are highly subjective. There aren't many breweries that I won't be back to, but Fox and Mistress just simply don't make good beer in my opinion. For the life of me I can't figure out how Fox is still open. Sticking with taprooms only in the Des Moines area, here's my list. I'm not including Big Grove because they're a year away from serving beer in the Des Moines area. I'm sure it will be great, but I can't rank someone who doesn't have boots on the ground and taps flowing. And yes, I consider Alluvial to be in the Des Moines area and I'm partial to anything Ames.
Tier A
Lua
Tier B
Confluence (B+)
Alluvial
Flix Brewhouse (solid, consistent beer)
Peace Tree
Brightside
Tier C
Exile
Kinship (on their way up. still new, and a ton of potential)
Fenders
Tier D
Twisted Vine
Firetrucker
1717
Reclaimed Rails
Court Av
Barntown (food is fantastic)
Tier F
Mistress
Fox (F-)