I've built a full piston valve, but it only had .787" porting due to materials difficulties, and it wasn't really worth posting. It also leaked intermittently.
My valve of choice on pneumatics has always been a burst disk of some sort, because reliability and power generally trump ease of use for me (unless you can't already tell

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If you could get a spring loaded ball valve to open fully in 2ms, it would be just as good as a piston valve. Until then, a piston valve wins.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.