I have one but haven't actually used it yet. I've only practiced so far.
It's not too difficult in my dark bag; the trick for me is to come up with a method in the light. At first I loaded it with no thought of being in the dark or in a bag, watching closely, holding it to my face and the like. Then I figured the best way for me to feel for the channels, etc. After I have a system, I'll just load and unload while watching TV, only looking at it when hitting a snag. I guess the secret is a lot of practice before putting it in the bag (and then practicing in the bag).
This is what I did for the huge Yankee 4x5 tank I got from ebay. I found the 2509 without the guide easier to load in the bag than the Yankee with it's guide in the light. I have used the Yankee to develop, which is why I got the Jobo reel and tank.