The fun really depends more on who is running the event and on who signs up. If the event (or your card) is stocked with moody, competitive prima donnas, it doesn't matter who the TD is, or who is sanctioning the event. On the other hand, if the event is well run, and the players have good attitudes, sanctioning doesn't make a difference to me.
But I've played enough sanctioned events, and with enough rated players, to have a feel for where my rating would be if I had one, and I don't feel the urge to pin down a specific rating for myself. In my very limited experience, I tend to have the most fun at Ice Bowls and Ace Races. One thing that surprised me was how hard a guy on my card took it when he carded a quadruple bogey on a hole at our Ice Bowl last month. He just got pissed off at himself for ruining his round, and tried to keep his irritation from spilling over onto us, but it affected the mood of the card. Later in the round, another guy on the card took something like a triple bogey on a short, easy hole, and just shrugged it off and kept having fun. Seeing someone else have a blowup hole and not let it get to him seemed to help the first guy, and things improved from there. I guess the moral of the story is that if you don't sweat the small stuff, it helps everyone around you learn not to take it as hard either.