I tried it for the first time in Victor Harbour last year and absolutely enjoyed it! We were there for four days, and I went to play mini-golf on all days - so much fun and a great, sociable activity!
Yes, it's a lot of fun and something that adults and kids can enjoy. There's a great little course at Dural that I like. Their cafe does great chocolate milkshakes too.
I have only played mini golf once. I didn't expect to enjoy it but joined in so as not to be a party pooper. However I was surprised to find it was fun. The experience has encouraged me to give other things a go even if they don't seem to be 'my thing'.