I have had mine for a little over 3 or so weeks, so no need to drain it yet. Due to poor planning, I mounted my rad on the outside of my case (as I intended), however, I have the barbs sticking out, so I wasted some tubing doing that, and it looks a little off. As it turns out, however, they'll make it easy to drain. Keep a bucket or whatever below the barbs as just twist them off (they are the lowest point on the loop), and tilt it back, and there ya go, it'll drain for me.
For filling it, I cut off a small piece of hose and stuck it on the end of a funnel and used that to fill it while mounted in my case.
In my excitement, I didn't tighten the barbs all the way down, and they were leaking a little (from the res). Other then my small oversights, it's been wonderful, and the kit is awesome. If you have the funds, spend it on some tubing though, because the stuff that comes with it sucks, and mine is starting to discolor. Nothing WRONG with it, but I like it all looking cool.