I just got my sideart from classicarcadegpraphix, and all I can say is WOW. It is incredible! I had some fears that it was going to basically be a flimsy piece of contact paper or something (like what you get at kinkos), but it is gorgeous, and it looks very durable (only time will tell). It is on nice thick vynil (adhesive backed), and it is just amazing looking.
I can't speak for their other printing (I've only got the side art from them), but I am super impressed and plan on using them for other projects now for sure. I am blown away at how good this looks (all of my other projects in the past, I just used Kinkos, so that is all I can compare it to, and it's just incredible how much nicer CAG is, you really have to see and FEEL them in person).