Burley Dash FM extended rails
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.
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.