I have a T-bar disgorger and a coarse fishing one which has small head on one end and large on the other and have used this more than the t-bar one.
Very easy to use, (if right handed) hold fish in left hand, hold line under tension in palm of right hand, hold disgorger with thumb and first finger, twist once around line, lay line in groove of disgorger and gently slide down the line until you reach the hook, then apply slight downward pressure until hook releases and then carefully pull hook out of fish. Easier done than said.
I found that a decent pair of self locking stainless steel atery forceps were easier to get and easier to use than the several different disgorgers you need for the various hook sizes. A big Conger can't chew them up either (most disgorgers I have seen are plastic) and once they are clipped onto the hook you can concentrate on removing the hook instead of trying to hold everything all at once.