Just switched over to Qwest fiber and thought I'd follow up my original post with my own speed test results for anyone who may be curious.
The 7MB service is yielding me about 6.1Mbps downstream and 700kbps up. The downstream speed and ping time (due to "interleaving" - don't ask) is slower than Mediacom's 8MB service (got about 7.6Mbps when it was working right); the uploads are about 50% faster. Overall, the difference doesn't matter much to me and I'm happy to ditch Mediacom and give this a shot.
I found a forum where they give some insight as to where they are rolling out fiber service in Iowa:
HERE.
Craziest thing I found, though, when I was searching around during this process is that Fairfield contracted with
LISCO (link) to provide 100Mbps up and down to everyone in the city and the rates were about the same as DSL and cable. If I lived there I'd be all over that!