gc valve differences

whats the difference between all of the gc valves. i was going to run the 450's even though i only have 2 5 gallon tanks and 2 compressors. or should i just go with the 350's. any difference in speed? im getting 1/2" valves also.

I wouldn't waste your money on GC valves. Go with Parkers or the Tork Valves.

450s 350s 250s is just there pressure ratings , id go with the 450s , iv been running the 450s for a year now

how so the smc's compare to them

I've used SMC and GC, and the SMC have been a lot more reliable