I always feel a tad under-dressed for this fancy of an establishment! Make sure to put your heels on and get your hair and nails done before entering so you don't feel out of place. All that being said, it's pure luxury. It's the closest you'll come to feeling like you are shopping on Rodeo Drive, without the judgement of buying a $5 top at H&M. It's the best of both worlds: you get to feel like a queen without being judged for not having the wallet of one.
There is a good mix of high-end shops, and budget stores that you will be able to find a little bit of everything, and most likely what you are looking for.