There are a lot of soft product reasons I like DL.... but to be perfectly honest, the biggest reason DL gets most of my business is because of their DTW/MSP/SLC hubs. Simply put, a lot of my domestic itineraries require a mid-continent transfer point, regardless of which airline I use. In addition to DTW/MSP and soon SLC just being nicer airports, I am much less concerned about missing my connection at any one of those three then pretty much any connection location AA/UA/WN offers. Problems causing delays related to lack of available gates, airspace congestion, tarmac queues, and even weather always seem to be much less of an issue at those three hubs compared to competition. And that is kind of a big deal to me.