Keep in mind though that the "20 years on reserve" is really on reserve only every other month, as UA has a rotating reserve system. (Still sucks compared to being off reserve completely, but it should be pointed out, especially to someone used to a straight reserve system.)
But in general, Fly is right. DEN is generally considered to have the worst flying in the system, and is very senior. Lots of Prairie Patrol (DEN-BIL-DEN-ICT-layover-ICT-DEN-AUS-DEN-SLC-DEN type of trips). But it is a nice place to live, which explains why people put up with the crap flying and seniority.