I definitely have to agree with Mike on this one - Hazelton Lanes will make most feel very intimidated - or in my case, very insufficient. Then again, if you don't want to hang out where the rich and successful do, then you might want to stay out of Yorkville.
That being said, Hazelton Lanes does have a ton of fancy pants stores that will clean out your wallet and fill that void inside you. They have a whole foods as well as tons of clothing stores, jewellery stores, home good stores, etc.
If you have the cash to spend, Hazelton Lanes is as fancy and upscale as malls get and its worth a visit. But, as Mike S. said, you'll get much better deals and a better bang for your buck at Vaughan Mills.