I have read on here somewhere that Frontline is not a very good product for b's in particular, apperantly they can have adverse reactions to frontline. I do believe that Advantage is an OK flea med. We have major issues here in Texas with fleas year around, so I am trying different things myself. I actually got Comfortis from my vet and it works amazingly well, BUT I am having second thoughts about it since it is pill and it stays in the dogs system for a month. I don't know what the longterm effects would be from that. It feels as if you are darned if you do and you are darned if you don't. My other dog, Westie(he is no longer with us), had severe allergies, on a range from 1-3000 he was in the 2800 area, so like I said severly allergic. I tried everything with him, and a few months out of the year he was on several different ones at the same time, and he still got fleas…poor thing. I am even looking into the natural homemade type flea preventatives, but don't know how effective they will be. Hopefully more members will answer your question so you can base your final outcome on several levels.
Good Luck, and let me know what you ended up with..