The response time of solenoids will depend a lot on how they are driven electrically.  Driving the voltage prior to opening to a level about 40 to 50% of the pull-in voltage will reduce pull-in response time.  Adding a reversed-bias zener diode across the coil leads to absorb the coil flyback voltage will cut the drop-out time (the higher the zener breakdown voltage, the faster the response time).  As stated, shorter mechanical strokes will give shorter response times also, as will higher force margins (force margin meaning how much more magnetic pull force is generated than is absolutely required to move the plunger against pressure forces.  More force = more acceleration = faster plunger travel).
The fastest valves I know of were used for the Voyager RCS thrusters, and had response times of about 4 ms (0.004 seconds).  They were made by Moog, and cost a bundle.  EG&G Wright components also made similar valves, which could achieve similar response times if operated per above.  Marotta had some too.  You may be able to get under 10 ms with an off-the-shelf direct acting solenoid valve, if operated as noted above.  Try over-driving a 12V solenoid with up to 24 vdc for a brief period (10ms or so) to "kick" the valve into possibly faster response times.
To measure response times, set up a dual-trace o-scope to measure coil voltage and current, and watch for a telltale "spike" (really more of a dip or bounce) in the rising/falling current trace to tell when the plunger has moved.

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