I always buy the 6 or 12 month. It is a great value.

Pros: Great Value

Cons: na

Frontline works very well for its intent. It works great for ticks, but not as good as Advantage for fleas. Ticks can still attach even when the animal is treated with it, but they will fall off soon after ingesting so much of the toxin.

Pros: Only tick repellant approved for cats !

Cons: not superb on fleas

The only headache with this is getting your cat to sit still as you apply it. It is awesome - frontline is vet recommended for dogs or cats. Costly but worth it

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[updated on 2008-02-20 15:35:05]:
I actually prefer this brand and use it moreso that the other brands I have used before. I buy it from my vet directly

Pros: This works great - vet approved

Cons: none

We use this alot and it is one of our favorites.
Works well, priced right and you do not have to go to a vet to buy. Sometimes I have found that you might need to reapply every three weeks instead of once a month for best results.

Pros: Works

Cons: n/a

I use this on some of my outside cats that like to go hunt in the woods, it works on ticks better then any other product I have found so far.

Pros: it does keep the ticks off

Cons: not so good for fleas