I never understood why people want to get paint mail order. Just go down to your local jobber and get the paint in person taking advantage of tips & advice they'll offer.
The paint offered by the above website is Sherwin Williams 4th Demension, comparable to Kirker, Omni etc. If it was me I'd stay away from it and use a quality paint.
I have used a lot of Omni and have been happy with it. I use it for overalls. The color match is better on the regular PPG line, but if doing an allover, Omni can save you a lot.