Yeah, I'm keen to try one. For me it was line ball whether I bought a Blokart or build a class 5. I even spoke to someone on ebay about transport costs to get their blokart down to me. The things that swayed me towards a class 5 (given that there were no class 6's available at the time) was:
1. it was about $500 cheaper than a secondhand blokart (class 6's will be even cheaper)
2. I had just bought a new arc welder and I was itching to use it.
3. David Rose is a really good source of parts and info (he ended up building a fair percentage of it for me

)
4. There is a club at Pt Gawler I can sail class 5's with.
Really the only downsides are I can't use a shadow and transporting it. But that said the club has a 2 seater I can take the kids out on and now I have a trailer. When my lads are a bit onlder I think I'll get/make them a class 6 to get them into the sport. (probably around the time I get a Standart

)