For Labs, Frontline is probably the better product. Frontline is lipophilic which means it is absorbed into the skin easier. Advantage and Advantix (both made by the same company) are not. What this basically means is that Frontline is much more resistant to water. Therefore if your lab loves getting wet, you will find much better success with Frontline. Now if your dog doesn't get wet that often (except for the occasional bath), it probably doesn't matter which product you go with.