New Flea Treatment?

Lola and Logan had a Vet visit yesterday and they tried to get me to buy Vectra 3D instead of Frontline.
I said absolutely no way when I don't know a thing about it nor have I researched it. The way she explained it was that it was stronger and you can put it on in 2 separate doses. That sounds like way to much chemical for my liking. Plus the dosage weight is up to 20lbs then you have to go 21-55lbs. Lola is almost 25lbs and I don't want her having up to 55lbs.
The way she explained it was this treatment attaches itself to the hair follicles and spreads that way so they might itch at first when the treatment is administered.

I don't know about this. Am I just being crazy? We are still on frontline for now.

I'd be cautious too, until you find out more!