Frontline and Advantage are both good products. I'm not sure if Advantage II does ticks if you have an issue with them at all. Double check, I know it used to be only fleas and Frontline Plus did both. I think Advantage recommends also using a separate tick preventive such as a collar. So I guess if you have tick concerns I would go with the Frontline Plus, since it would take Advantage II plus something else and then the cost is probably the same. You can probably ask your vet or look up maps of where different tick diseases are if any are in your area.
Good job for not using the over the counter cheap ones too! I have seen way too many pets react from those in varying degrees and when you call the companies they usually don't seem concerned and just fax over the reaction protocol. Garlic can have toxicity and it is like some things that may effect one pet more than others. It has the same thing that is toxic that is in onions (onions are much worse though and contain more thiosulphate that is what causes the reaction. Garlic probably has to be consumed in higher doses for toxicity.