This good explanation from Tire Rack summarizes three types of valves:
1. Rubber Snap-In: Available for .453 and .625 hole diameters, 65 PSI maximum. These have an all-rubber look, exposing only enough brass to screw a cap onto.
2. High Pressure Snap-In: Available for .453 and .625 hole diameters, 80 PSI maximum for .453 and 100 PSI for .625. These have a rubber-base look, exposing a clearly visible length of brass between the rim and the cap.
3. High Pressure METAL Clamp-In: Available in .453 and .625, both can handle up to 200 PSI.
I should be able to say "Nuff Said" at this point but should add:
1. E-Series comes with .453 holes.
2. At 80 PSI we max out the rating of "High Pressure" Snap-In valves.
3. Those who want to go to Load Range G tires can't get away with only getting Clamp-In valves because the Wheel itself has a max pressure rating of 80PSI.
4. Many Tire Jockeys became Tire Jockeys because it pays $.50/hour more than flipping hamburgers. Without supervision they'll pick what fits in the hole. Unless you specify METAL.