I've used Advantix for a few years now on our 50 lb. Aussie mix and it is wonderful. This year I tried Frontline Plus and it didn't do anything for our dog. She was covered in ticks after our last camping trip and has been scratching from fleas ever since we made the switch to Frontline. I have a flea allergy so it's really important to me that we keep the fleas out of our home. I'm definitely switching back to Advantix and getting rid of the worthless Frontline! Both Advantix and Frontlineleft an oily spot where it is applied but that disappeared by the next day. It didn't affect us since my...