Even though I am a recreational rider, I do enjoy riding fast and have lots of hills and mountains to deal with on any ride. in an effort to minimize pain and increase efficiency, I paid for a pro fitting that included finding my body flexibility, better than many crit racers half my age, and with some magic formula, know where everything should be, incluing cleat position. This fitting was good for a speed increase and had the desired effect of reducing pain.

During the fit/coaching session the discussion touched on pedal technique. From my recumbent riding, with a great deal of recline, I did develop a pull that was more than enough to feel pressure on the top of the shoe, but I was never able to get that degree of pull while riding the Trek. He told me, circa three years ago, that the current spin training was to "kick forward" at the top and "scrap mud" off the bottom of the circle, don't think about pushing down or pulling up.

I found that changing my thoughts about how to apply the power had the effect of increasing my spin by 5-10 rpm, but more of interest to this thread, on a long hard grind, if I concentrated on that, to the exclusion of the usual downward push, I gained 1-1.5 mph over just pushing. He said they had data of pros on trainers with infrared film showing where the muscles were working to support this, but even if not true, I have a result I like, and others I've told about this confirm the increase in climbing speed.

Also, in favor of clipless and speed, I've hit bad spots in the pavement that lifted me off the saddle. I came back down right where I was because my feet were attached.

When I ride a bike w/o clipless, my feet slide off, usually on the bottom of the stroke. While I've not tried soft soled shoes and pedals with teeth to grip, I can't imagine that that combo would hold me to the bike on a 30+ mph descent.