99 Designs was great to work with. Their website has a very intuitive interface, and the process is easy to follow. I emailed them early on, whining about the lack of entries, and they were more than willing to help. I would do business with them again, but probably not in the way you would think.
After starting this process, I was researching how to involve more designers when I came across some articles about the evil of spec work. While there is a great advantage for me to receive multiple design concepts, only one person will get paid for their work.
When this sunk in (I’m slow sometimes) it weighed on me throughout the contest. It changed my perspective on changes I would ask for. When I stopped being interested in a design, I stopped asking for changes because I didn’t want the artist to spend their (unpaid) time working on it. I still like the idea of receiving multiple submissions, it’s been a great experience, but I think there is a better way. In the future, I’ll continue working through 99 Designs but I will hire the designer directly instead of using a contest.