If your dh is going to work in Oud Metha, traffic can be a bit meh round there. Personally if your allowance is unto it I would live in Jumeriah. We currently live in umm Suqeim and it does only take 20 mins to get to our Metha but.....traffic is a nightmare. Much nice over on the beach side near Jumeriah than mirdiff, although mirdiff is cheaper.
Regarding schools do check if dh company will pay preschool fees, most companies don't and the costs are the same as school fees. There is loads of anti gems feeling (gems is an education company) having said that ds and I are more than happy with his outstanding school.
If you lived in Jumeriah 3, dh could easily get to work, schools could include, dess, jess, wis, star, Jps, safa, and horizon. Also kings at a push. Lots of good nurseries. Get the school then the house then the nursery.
Make sure package includes, good health ins, school fees, shipping plus ins (usually the same cost about as the container), housing allowance, you need a look see trip as well if poss.
Take a peek at expatwoman and also dubizzle so you can get an idea of how much property costs. Ignore the pics most are stock and bear no relation to the real villa. Also FYI most agents are dreadful and will not entertain you until you ar actually ready to move. Most peoples co put them in a serviced apartment for 1 month whilst they decide where to live and get everything sorted.
Yes it's tax free but it can be very expensive, so do your sums carefully. Having said that we've been here more than 5 years save a fair bit and have a good time and get to travel a lot.