Gravity is fine as well with plate chillers. I have a couple Shirrons, and they are as fast as normally draining wort from your brew kettle. Always a good pitching temp, and in my opinion (always the scary part to hear), the least about of pressure the better, as it allows for less chance of something getting jammed up inside of it, like hops and other solids. Like I said, thats my opinion anyway.
Up Next: Cherry Chocolate Rye
Up Next: Gold Nugget IPA
On Tap:Pawtucket Patriot
Dead Soldier:Hop Rod Rye Stout
Dead Soldier: Imperial Hell Fire Ale