In near-daily use for 3 years. Harness and back pocket thing were replaced (with Burley parts) after 2 years. The seat was still working fine, just outgrown, though I admit the seat padding has come unstuck from the plastic and is held on by string. $40 OBO.
Note that this is the Frame Mount (not rack mount) Extended Rails version. The Burley website explains how to measure your bike to make sure it will fit.