Hi there

Interesting choice. I cannot speak for Dubai, but have been happilly living in Singapore for two years now, and can tell you the following:

I would definitely ask the company to pay for relocation. I think that you'd find it's cooler in Singapore in summer than in Dubai. Plus I can think that in Singapore for you as dual national, to apply for PR status, would be far easier, which entitled you far quicker to buy property in Singapore, it's a market where you cannot lose out, since prices simply keep going up. It's a fantastic investment to make.

Generally the cost of living can be high, but your package should easily match that.
We came over on a "normal" ie non-expat salary package, and the two of us plus two cats are happilly living in landed housing on the East Coast. I know the normal expats packages are far higher in value, but you would need to check that with the company, don't be scared to talk nitty gritty, this concerns not only you but your entire family.
You would find that some things are more expensive, some are far less, it all equals out in the end, plus, you have the rest of the world's best exports coming through Singapore, so you do eat like kings, both of us have gained weight.
As for schooling, it can get pricey, but not overly so and there is a large variance in schools, types, focuses, and the education is top notch, plus, they focus on education from early on, and the standards they hold is really high, kids walk out of their schools with a decent education.

Cars are more expensive here due to extra charges, they are looking at keeping the number of cars on the roads down, which is why they have top class rail and bus services, imaculately run, ranking amongst the top in the world. And cheap, too, to accomodate the vast majority who do not own cars, and do not need to with public transport being as good as it is.

In Singapore you are also central to so many places, and can travel on holliday all over.

Like Dubai, there is always construction everywhere, knocking down the old to bring in the new. Roads and things get fixed immediately, public safety is top priority.

4 bed villa in 'good' area - S$3000-15000pm, and you pay three months in advance for security before moving in. To buy you need to have PR status, as well as having contributed 2 million to the economy by then.

Toyota Prado 4L - D$60 000-120 000 depending on the age of the car plus the value of the Certificate of Entitlement to use the car on the road, one of the costs that add so much to what one spends on cars. (then there is parking, due to scarcity, a company may charge S$30-40 per day to park on their premises during working hours.)

Fuel - S1.50 (approx) per liter

Laptop - S$1500 - 4000
meal for four in classy restaurant (no booze) - S$450-1000
Bottle of wine in restaurant - S$125 (general approximation)
School Fees - Primary S$145 Secondary S$210 Junior college S$350. For children of Singapore Citizens or Singapore Permanent Residents and dependants of Employment Pass and Skilled Work Permit Holders, the monthly school fees payable for the first 2 years are S$3.50 for primary, S$6 for secondary, and S$7 for pre-university levels. For the third year onwards, the school fees payable will be determined based on their citizenship status.
You need to contact Ministry of Education - MOE Customer Service Centre at DID (65) 6872 2220, Fax No (65) 6776 4617 or contact (at) meo dot edu dot sg.

I apologise for the jumbled information, I hope it helps.