The Festos are great - unless you need volume, say, for a ball launcher with a couple of 1.25" diameter cylinders. Then, they fail miserably compared to a valve like Automation Direct's:
http://www.automationdirect.com/adc/...9/AVS-3211-24D
The Festo VUVG has a Flow rating of 0.22 Cv (220l/min) vs. the
Automationdirect's Cv=0.78. The numbers speak volumes (pun intended).
Further, Automationdirect charges a fair price for pneumatic components rather than what they can get away with... compared to - ahem - some other suppliers. On top of that, they give FRC teams a free voucher every year, and always offer free shipping > $49.
No, I do not have any affiliation with Automationdirect - I merely appreciate what they provide to FRC.
Other thoughts: Be sure that whenever you remove a hose from a fitting that you snip off a bit, so that the fitting barbs can get a fresh bite. Also, leave air pressure in the system after matches to insure you have no leaks - and if you do have one, use soapy water applied with a small brush to find it.
A pneumatic cylinder pushed our ball into the shooter this year, and we chose to not have an on-board compressor. Through diligence and constant monitoring, we never ran out of air on the field.