I'll second what CRX says, done nearly 30hrs in my Nipper since June and it just gets better the more I fly it!
OK, its no Pitts but with 1000fpm climb and decent roll rate, as Paul says it gives more than enough fun for £20 an hour!
If you dont want the worry of hand swinging etc you can always go for the 'civilised' Jabiru version with an electric start and extra 20hp.....handy if your a 'big lad' like myself!