I have had good and bad experiences with Zulily.
Bad:
1) Many of the clothes I ordered were NOT listed as see-through on the website and did not appear to be see-through from the pictures, but they are see-through. I am unsure what to wear under all of my see-through tops and dresses that I now own. To reiterate: this has been a common occurrence.
2) One of my items that I ordered (let's say, out of 20 items) never arrived. Instead of giving me a full refund (~$40 I think), I was only given a $10 store credit.
Good:
1) Many of the clothes I ordered are very unique and pretty
2) All of the clothes I ordered seem to be much cheaper than elsewhere and so even though I lost money on see-through items and one item that did not arrive, I still feel like, overall, I made some good purchases.
However, as you can see, Zulily is inconsistent and unreliable (and possibly dishonest for omitting information). So, I wouldn't really say it's a good business.
Take your chances.