...might be getting in too late on this one...Mike, from what I've read of your adv. efforts, you seem to be good at focusing an area and hitting them with DM, and I assume you do other things, YPs, newspaper,etc.
So to Valpak. Here is my experience. The money is not as well spent as DM. But......the jobs I got from it were jobs I'd have NEVER got any other way. In other words, it can be the only aggressive adv. you may ever get on certain homes. What that meant for me, was getting some rediculously high-end jobs. Not the subdivision type. I mean, the place where you see a mailbox but no house......it's the house you see from a parallel road and wonder how to get to that monsterous house....just seems to be dangling off a hill. Those folks don't get pounded with aggressive advertising like the subdivision type, so it might be the only effective way to reach the top of the market.
So.....I think Valpak is valuable, just not as a primary adv. source. Maybe for the 4th or 5th thing you try.