Why not publish your results here, Musket? Then we'll know what you're sans or avec today!

Having been involved in creating a simple feedback survey for a number of events I've been involved in organising, the single most useful bit is leaving a large space for free text comments: it does mean you have to actually read them, but it does help to highlight any perceived problems or suggestions for future events. You don't get that from tick boxes or even from scoring systems.
And in this day and age, it's becoming increasingly necessary to provide evidence of "economic impact assessment" for existing or potential funding bodies. I don't think they need to know how many A levels or degrees you got, but how much money you think you spent while in their lovely town is a relevant question, whether on the festival or event, or elsewhere in the vicinity, and whether you patronised any other visitor attractions or shops.

It's interesting that the survey form commonly used by various organisations is Survey MONKEY: "you ask monkeys, you get monkeys"!