To give you an example, the appartment I am in here in Abu Dhabi which I consider (having spent 10 years in the Gulf) to be of the living standard appropriate for this part of the world is identical in age and size to my appartment in Muscat.
The location in Abu Dhabi whilst a nice area is not 'premium' compared to my flat in Qurm (Muscat). This info is important when factoring everything in.
I pay 117,000 DHS annually, or approximately 10,000 per month with the latest rent raise etc for my Abu Dhabi appartment. This equates to approximately 12 - 13,000 Omani Rials with the exchange rate (DHS is slightly stronger than the Rial in conversion).
My appartment in Oman was (3 years ago) 300 Rials per month or 4,000 OMR per year approx.
Now even if the rents have doubled (which would be the worst case scenerio based on my research) in Oman , the difference is still massive and Abu Dhabi is sporting rents worse than Dubai now due to Accomodation shortages.
Now as for Schooling etc. I don't have any legitimate children that I have to support so can't help you there
Most of the other day to day prices are comparable (water, elec. etc).
The salary here at the center for the government employee contracts as a line controller is 33,000 Per month which includes everything, no additional allowances etc.
Hope that helps a bit.