Input needed--flea and tick prevention

Hi all--my lab is currently on Advantix II for flea and tick prevention. I used to be able to buy it at my vet's office, but they have stopped carrying it and started carrying Vectra 3D. I buy the Advantix II either at Petsmart or online. I've never used Vectra 3D and am hesitant on switching to...

Source: http://www.lab-retriever.net/board/general-health-issues/7388827-input-needed-flea-tick-prevention-new-post.html

Mastiff Maltese Malamute Saint Bernard