I use Advantix II on the Fuzzbuttz, and don't have any kind of bug problem. I live in a wooded/semi-rural area and we don't do any lawn treatments here. Granted - the dogs don't actually go out into the woods, but there are plenty enough just in the yard to hitch a ride on one or both of them.
I too heard that Frontline seems to be losing it's effectiveness. Maybe it's a geographical thing tho - depending on what area of the country you're in. I've always used the Advantage/Advantix line, so I can't speak negatively about Frontline, based on my own experience.