I always check before I purchase. The site is simple to use and I almost always save money. I dont know why anyone would not take the few seconds to sign up and purchase via this site.
I've ordered a number of items from Zulily with absolutely no issues. The one time I needed to return an item I received a full store credit, though I did have to pay for shipping. Since then I have had absolutely no issues.
My only complaint is that it takes so long to get most items.