I live in Dubuque and was really happy when Dimensional opened. I used to frequent 7 Hills a lot, and while their beers never really blew me away, they were decent enough and as several people have already mentioned, do food really really well. I really like 7 Hills Red Ale, their west coast style IPA and their Brown Ale. Aside from their basics though, I really don't enjoy most of their seasonal/experimental stuff. Dimensional does that stuff way better and have a better variety of beers overall. Lived here for 4 years and still haven't tried Jubeck.
Other Eastern Iowa breweries I've stopped at that I haven't seen mentioned so far would be Tellurian in Charles City, Lime Stone in Osage, and Lake Time in Clear Lake. I especially enjoyed Lake Time Brewery in Clear Lake. I don't know what tier any of them would be on, but if I had to put them in order for myself personally, I'd say
1. Lake Time
3. Lime Stone
I wouldn't call those 3 "eastern Iowa" necessarily. I would probably flip Tellurian and Lake Time, but I really enjoy all 3 for different reasons.
Lake Time: make some decent versions of nearly any style. Their peanut butter porter is the best of that kind of beer I've ever tried. I generally think their IPAs are pretty good, actually. The tap room is pretty cool, being in an old house and just having a real comfortable feel.
Tellurian: really good hazy IPAs and some interesting sours. Probably the "trendiest" in terms of modern styles among this group. I love their overhead door open taproom and they have really good food trucks a lot.
Lime Stone: they make some very good malt forward beers that don't get too sweet - or as I've told their owners, it's beer that tastes like beer. Their Big Bin Porter is just a really good regular old porter. They did a Maibock this year that was great as well. It's a cool taproom with two levels of seating and some interesting historical Mitchell County memorabilia, and an axe throwing set up.
All of these are worth your time. Not sure on the affiliations of all the brewers/owners, but one of Lime Stone's owners/brewers is a huge Cyclone fan if anyone here's looking for an intangible reason to pick one over another.
If you're in that area, Worth Brewing and Fat Hill in Mason City make some really enjoyable beers, and Fat Hill's taproom is beautiful.