I use Sentinel and LOVE it. It is cheaper if you get the entire 12 months at a time (recommended, since heartworm protection is really needed year-round even in cold weather). I pay around $100 for 12 months.
My babies are not outside that much, but I've never had a problem with live fleas. The Sentinel does act as a flea birth control, killing eggs. I also bathe weekly and I can't stand the chemical smell of the topical flea treatments. The shampoo I use (SheaPet) also has essential oils that help repel fleas. With this being a small tablet, I just squeeze it into a piece of cheese and have no problems with the girls eating it right up.
I give it
!!