I've done my local one 3 or 4 times now I think. Not done it for a while. They are pretty annoying because the courses can vary so drastically, ours is actually all on park land with tight turns. It's a very slow course but there are some out there which are 100% flat tarmac with little turning so they are much quicker. It's no gauge really or a good measurement of where you are at against the competition on their courses round the country. I can't remember who it was or what his time was but someone quick came and took our course record so there was talk a few of us getting together to work and see who could get it back but nobody mentioned it for ages actually. Wee winter project maybe at some point on a cold frozen ground day when it'll be faster!
The last couple times I run it was to use it as a tempo before doing a session as it's right next to our track which is handy. They are very good idea though and definitely worth going to and getting involved with to see your progression and keep you aiming towards improvement. Plus they don't cost a penny! Win!