I would chose Dubai. I have a friend who has just moved out there and is having the most amzing time. Granted she doesn't have kids but the lifestyle, cleanliness and variety plus that it seems safe and unrestrictive would definitely sway me there!

Where ever you go, no matter how great the place is there will always be some negatives about being away from home. You just can't replace friends and family and that has been really hard on me. but i guess you already know this and plus that you are only planning on two years (maybe!) i would say go for it!
good luck choosing
Julie x