I guess if you were to get it on sale they would be worth it, it's just the matter of spending $500+ on a pair that isn't on sale because I honestly think the quality isn't worth $500+ at all (I own Louboutins, Valentinos, Nicholas Kirkwood, etc and I can definitely say that SW's quality is not on par with any of them, it's more on par with Zara shoes).
I recently purchased a pair of Charlotte Olympias instead of SW this summer sale, I haven't seen it yet but I hope it won't be disappointing like SW although I honestly prefer SW's designs by a lot.
I received my flamingo heels today (which are absolutely gorgeous!!!) but I can kindof see what you mean about the quality compared to other brands...
It's nothing hugely noticeable (on my pair anyway), but her shoes just aren't finished off as well as other brands. However, lucky for SW no other brands have anything similar to her styles, so she can get away with it for the time being. If her designs weren't so unique, she would probably struggle a bit more with this quality issue.
I do hope she looks at improving the quality of her products in the future, because her designs are amazing!