My company sent me a Mercer comparison hen I transferred and indicated it was approx 13% more for the shopping basket they had chosen.
The Big Mac index reckons Switzerland is twice as expensive as Switzerland: http://www.oanda.com/products/bigmac/bigmac.shtml
I reckon the reality is probably somewhere in between.
I notice the cost of meat / fish, taxis, eating as being the biggest difference - maybe twice as expensive here. General groceries also seem significantly more expensive. Clothes, electronics, white goods seem similar. Luxury European cars like Audi and BMW are much cheaper here although Ford / Opel and Japanese cars probably similar price. Petrol and diesel are more expensive (20% more?) here. Didn't use many trains or buses in Oz but trains in Switzerland are excellent and cheap with the half price card.
Not sure about renting (guess Geneva is expensive?) but the one thing that seems much cheaper is a mortgage - around 3% vs 7% in Oz but you need to put down a 20% deposit.
Any maintenance - plumber, sparky, rennovations etc cost the earth here.
But like in Sydney the great outdoors is beautiful and comes for free and Lake Geneva with the mountains in the background is a match for Sydney harbour (in my opinion...). And you get the skiing which is great value for the world class resorts you have access to.
Health Insurance is really expensive here although my few experiences with doctors/hospitals have been very good.
Although people say taxes are lower, once all the deductions are taken off (AVS, pension etc) there doesn't seem to be much difference in the final percentage deducted from my salary slip!
Basically if you want a nice place in central Geneva, buy fresh food, eat and drink out regularly and get cabs you might spend 50% more than you would in Oz or more.
If you live somewhere less central, buy a second hand car or use the train, spend your leisure time outdoors you can probably get by for 10-20% more.
Switzerland is a great country though. I loved Sydney and was hesitant to leave but haven't regretted it.