It's cheaper to buy the 5S off contract at $650 and take it to Straight Talk ($45 a month AYCE data/minutes) than to buy the 5C and pay $100 a month at AT&T for two years.
Not worth it for you
I really don't think having fast, hassle-free internet access on the go is an edge case. Isn't that one of the main reasons people buy smartphones?
ha - I had 6mb dl on 4g w/ AT&T iPhone 4S and moving to the iPhone 5 w/ LTE made it 24mb dl. Overrated? Maybe for you but, whenever a company triples my service and doesn't charge me more money, I'm happy to take that deal.
[1] http://reviews.cnet.com/8301-19736_7-57602923-251/straight-t...