US Cellular is a regional carrier.  Where they own their own towers coverage is usually excellent.  They concentrate on rural areas and having full coverage there.  They tend to be the most expensive carrier due to the rural coverage.  There are places in Wisconsin where only USCC works.  They know this. 

My wife has a Sprint unlimited account for $50 in an iPhone 7.  I have an iPhone 8 on ATT from my off farm job (They pay $30/line for 15GB data and unlimited everything else).  I have two kids with iPhones on cricket for $35/line.  They are 5GB unlimited lines.

In my opinion cricket is the best deal currently.  You can get an iPhone SE for $99.  No one else is this cheap for an iPhone.  It is an almost $200 subsidy.  Not the newest phone, but I think that is a fair price and the service fee is right too.  Their high speed data is 8 Mbps download.  The upload is not throttled (even after you burn through you 5GB.)

My wife on Sprint has an old SERO plan that also includes a device subsidy.  He iPhone 7 was $199 with a two year contract.  Sprint essentially gave us $399 subsidy for the two year contract.  That's worth it.  Most carriers now want you to pay full retail for the device, lease it for full retail or more (you don't own it at the end) and their plan prices are just as expensive as when they have subsidies.  The only difference is no contract. 

If you have good ATT coverage in your area, I would go with Cricket.  Do it all online and have a good/great plan for $35-50 per month and an iPhone for cheap.