The new Advantage?

The last time I bought Advantage (last month), I noticed it was
considerably more expensive. The clerk at the pet food store told
me that the company had changed the formula by adding a few things
to it, so that it's more like Frontline (or Revolution? can't remember
which - yes, I know they're different).

Has anyone used Advantage with the new formula? Good results? Anyone
experience (or hear about) adverse reactions in cats who had previously
been fine with Advantage?

It's getting to be time for my cats to get their monthly treatment,
but I'm a little apprehensive about it because I'll be giving them
something they've never had before. I'd appreciate information or
advice if anyone would like to give some.

Thanks,
Joyce

--
"Bacteria, with a few more bells and whistles."
-- Bonnie Bassler, describing human beings