Thanks for the info, I currently have a 11 year old yammy 40hp 4 Stroke tiller model on the back which starts first time and runs very well despite having compressions of 40 40 and 170. I've had it checked by a couple of different yards and they are amazed it still runs. I guess that says something about yamaha.
Looks like i can't go wrong with either, so it will come down to cost and the best deal I can get in the sydney area.
Thanks for your views.