Has anyone used CatMD maximum defense Fipronil flea and tick drops for their kitty's? Was in the store to purchase Advantage 2 but the lady working in petsmart said this works just as good. I did some research online and it has the same active ingredient as Frontline. Should I spend the extra $$ on Advantage 2? This is for my strictly outdoor kitty's! Is there any place I can get flea drops for cheaper? It gets so expensive and adds up so quick. Thank you!