Used these to replace some cheaper Cat6 keystones in an office where certain hard-wired endpoints were having quality-of-service issues. Sure enough, after re-terminating with these, link-layer quality was stellar, as it should have been from the start.
Specific reasons why KeyConnect is a better mouse trap: 1) the LeadFrame, which is a full-length wire from the receptacle all the way to the IDCs, without any silicon or solder points to fail in between, and 2) the termination bar, which is a guide, separator and fixation point, all in one, ensuring consistent terminations that hit spec every time.
The only item I would say could improve these jacks would be a snap-on cover for the IDCs, like you find with most equivalent models from Leviton, Hubbell, ICC, etc. Other than that, a nearly perfect keystone design.