1) What happens if you don't deliver in 24 hours? Can I bet my business on your promises?
2) What is your copyright assignment language? I'd like to know that before paying for anything.
3) Same deal for NDAs - Where are you located? I can't send certain info overseas for example.
4) "Chicken" is misspelled in one of your portfolio images. If I were you I'd either fix it or remove it because it looks sloppy.
5) Devils advocate here: What's stopping me from arbitrage? I submit a job to you every day for 99designs projects, and then submit your work as my own. Shoot I could probably even write a script for this...