The preloader "can" make it less reliable, but I have almost never heard of one failing. Hell, anything can fail.
Mostly you set the front shock where you need it and never again, no need for a remote preload adjuster on the front. Even if you did want to adjust it, it is easier than the rear because of easy access.
Aftermarket shocks are much more rebuildable, and cheaper to rebuild, than factory shocks.