Yes I keg hop all the time, I use those simple stainless screen tea "balls" that come apart. I find that you need to give a few days at least, like a week, then drink away. My kegs never last that long, so I'd say the longest is six weeks, and the flavor is fine. Right when you get to the bottom of the keg, you can tell when it's almost gone because the hops flavor gets more intense, and you do get a little grainy or grassy flavor out of it, but we're talking the last 2-3 pints before it kicks.