What's the difference between Keurig K-Classic, K-Express, and K-Elite?

The K-Classic is the original three-brew-size pod machine. The K-Express is the more compact budget model with a strong-brew button. The K-Elite adds temperature control, an iced-coffee setting, a larger 75-oz reservoir, and programmable auto-on. Mainstream press coverage and r/keurig discussions consistently position the K-Elite as the feature-complete pick and the K-Express as the no-frills option.