I live in Tick Central (northern Wisconsin). Have always used Frontline. Consulted with the vet about switching to Advantix. His advice was to stick with Frontline, because ticks will still occasionally attach with Advantix, and this is a serious area for Lyme disease. If you don't have as many ticks and if you have other problems, something else might be better in your area.
I read elsewhere that the patent on Frontline has now expired and a cheaper, generic version is available at Wal-Mart. I still have some Frontline left, but will check on that.