Monday Night Football uses SuperShooter 25 outfit and pretty much has since the show debuted on ESPN in 2006 (although the truck itself has been upgraded a number of times throughout the years). Same goes with ND3 Sunday Night Football's outfit which they've used since 2006. ESPN primarily uses NEP (who basically own everyone these days) and Game Creek for their big shows. Saturday Night College Football and the National Championship are usually done out of a Gamecreek truck.
The biggest differences I've spotted is not so much one of resolution, which as many others have stated is often a very overrated variable (contrast often is the primary determinate of how sharp something appears as well as focal length and the ability to discern edges between objects), but rather the cameras themselves. I've noticed the shows that are shot with Sony cameras (SNF, ABC Saturday Night Football, etc) tend to be a little crispier than the GVG cameras (MNF). I think the GVGs are a little bit softer out of the box (European design) than the really edgy/uber-saturated Sonys (which are known to be almost excessively snappy). During the NBA Finals ABC/ESPN often has used a truck with Thomson cameras at one venue and Sonys at the other and the difference, even with the same crew is often pretty striking. One venue usually looks a bit snappier than the other.
Same goes for ESPN's Sportscenter shows. The LA show uses Sonys and looks noticeably sharper than the Bristol show (in fairness LA is a 1080p native facility and the Bristol show appears to have the detail dialed down a bit).
I have noticed that ESPN's Monday Night Football looks pretty good this year though. The only real standout in terms of just horrendous PQ (to me) is some of the ESPNU remotes which are just notoriously noisy (seriously the internet feeds look better). Not sure what that's all about.