My wife and I daysail, and camp cruise our old j-24. I still do some beer can racing with it as well. To me, I don't know why everyone wants to change the boat. Leave it alone. Bang for your buck, you can hardly do better. As for comfort as a daysailor or camp cruiser, I can tell you it is terrific. Is it the most comfortable ever designed? Hell no. However, with addition of a couple of staduim seats while at anchor, and only running the blade when sailing with two or three crew, the boat works really well. We routinely use ours for weekending. We are not exactly young either, and for the two of us we are quite comfortable. I would also say, that when rafted up with Catalina 22 or Tanzer 22 or 26, we find we have more room (due to the beam of the J-24) and are just as comfortable. Moreover, I always get the anchorage first - even with just the blade - and my wife finds the smaller foresail just too easy to snap over and cleat using the Lopez blocks. I'll admit, I wussed out and pruchased a Doyle Boston asym cruising kite with a snuffer as my crew just weren't that "enthused" about flying the chute. My logic is I'd rather fly the less efficient asym more in a season than not getting the kite up at all. With the two of us, the boat flies with the asym.
My opinion the old J-24 is a good all purpose design. Yes, there are better, newer, faster. There always will be. However, and old J can have a wonderful second life as a cost effective racer cruiser which is what I believe was the original design brief. It works well for us.