I learned at a controlled field, but we would do landing work at an uncontrolled field.
I think it was a good experience. I learned out of ADS in the early 90s. It was/is a pretty damn busy single runway airport in the middle of suburban Dallas. All kinds of prop and jet traffic in and out of there, plus it's underneath DFW's airspace.
It really forces you to use the radio from almost day one. Using the radio is a little overwhelming at times in the beginning, but you'll be happy that you can talk just as fast you the controllers can by the time you're done with your private checkride.
Of course, it was nice to go to uncontrolled fields for the pattern work just so you don't have to wait around for other aircraft that much. It's nice to know both sides. I fly in some of the busiest airspace in the world at times, but at other times I find myself saying "South bend traffic, blueridge 6*** 10 miles out, left base for 27L" (I can't remember if SBN closes, it's one of those airports up there, though!)