Frontline doesn't work in Vermont according to most Vermont Vets, and i would agree with them.. It never worked for any of our dogs.
Vectra has worked well for ticks and fleas. We have a lot of nasty ticks here and also mosquitoes.
And i will always use Heartguard.
In the dead of winter, i use revolution, because i dont have to worry about ticks and it covers flea and heartworms, etc..
However, I love Vectra because it kills on contact, the ticks don't have to bite first, so i use that one and heartgurad in the summer, because Vectra does NOT cover heartworm. The last thing I want my dog to get is Heartworms, which is why i give hearguard specifically in the summer.
Winter she gets just revolution. As it covers flea, heartworm and ticks (it is not on label because it takes a while for the ticks to die). But i do not have to worry about ticks in the winter anyways.
Summer, spring, fall she gets Vectra and HeartGuard. Covering fleas and ticks (kills on contact) and Heartworms.