I'm sure that quick-links are reliable, but I don't bother using them on my fixed gear bikes. Unlike modern road chains, 1/8" chains aren't riveted, so there's no problem using a chain tool to push a pin put far enough to open the chain, then push it back in place to re-join the ends.

Riveted road chains don't tolerate that, because pushing a pin out breaks the peening on the rivet that secures the pin, and re-joining without a quick link leaves a pin that can disengage from the link at an inopportune time.