It depends on your Job and maybe where your children might be in school. If it is convenient for you to live off HK Island, you may be able to save money by doing so. You will get more for your money in Kowloon, and the NT.
As you may know from another thread here, I am partial to the West Kowloon area, and especially Olympic/TKT:
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But there are other areas worth investigating. For example: Tung Chung, Park Island, and maybe even somewhere like Kam Sheung Road / Yuen Long. But if these areas are inconvenient for your living and working arrangement, I would not bother.