When we first signed up with 4over a couple years ago I remember it taking forever to get set up as a vendor and to get samples. It's worth it, once you're a vendor the process is fast and painless and their product is top notch. You MUST know what you're doing when designing, or your color will not come out right, but that's not their fault. We've sent hundreds of jobs to them and have had to reorder maybe 5-10 jobs because we didn't have the file set up right, too much magenta here, bleed was too small, etc.. Take your time, make sure your file is 100% correct and it will come back perfect.