i have now experienced both, and for what i got for my money privately the first time, compared to public the second, if i have a third baby we will be going public again!
2.5 years ago it cost me about $2000 out of pocket. had i gone private again it would have cost me close to $3000. the problem (aside from the OB's fees going up with inflation plus a bit extra) was that medicare no longer gives as much back on the huge "management fee" that the ob charges around the 20 week mark. even if you have reached the medicare threshold you will still end up paying a huge proportion of these fees yourself.
the easiest way to figure it out would be to ring a few ob's and ask for their fee schedule to be sent out, that way you will have the medicare item numbers, then you can ring medicare (may be best to wait for the new year in case they change it for 2011) and find out what you will get back.
as for service received: yep i got to see the ob at every checkup, but i saw the midwife for longer as she did the checks, the ob just did a quick 30 second u/s each time. the dr was there for the birth but its not guaranteed. your own room also can't be guaranteed - if it happens to be a busy time at the hospital when you go into labour you can end up sharing. when i went in for DS1 there were 32 rooms in the mat ward and they were all full so i ended up in the surgery ward (my own tiny room though). i was moved the second night into the mat ward with my own room. the room was lovely, i had a fridge, tea and coffee facilities etc, double bed so dh could stay (he stayed 4 out of 6 nights) and on the last night we got a candlelit dinner with wine. so that bit was nice. however because it was so busy we didn't get much attention from the midwives, felt we were in the way as they were always rushed and didn't have a good start with bf (ended up ff when we got home).
at the public hossy i was in a shared room the first night (but no one in the other bed so it was like my own room). second night was with another lady, but then the third night they moved me so someone else who had a c-section could use the room. i was moved to a private room in the surgical ward with a balcony, views of the ocean, and a lovely sunset each night! there wasn't a fridge or tea/coffee facilities in the room. the food was just as nice as the private hospital. only a single bed so partners can't stay (but dh couldn't anyway as we had ds1). i did get much better attention from the midwives, didn't feel like they were rushed to get away to their next patient, more lactation consultants available, and they had a visiting midwifery service too, and loaned me a hospital grade breast pump for a week for free!
all up the public pregnancy and birth cost me $180 for the 12 week u/s and that was it.