I don't personally use Frova as I cannot use any of the triptans (basilar migraines), but my aunt uses it with great success. I believe Frova is most often prescribed for women who suffer from menstrual migraines although it does work with other migraine types as well.
I know it is sometimes prescribed a little differently than the other triptans if you are using it for menstrual migraines. My aunt takes it for a couple days before she gets her period every day - kind of like a preventative. She then takes it for the first 3 or 4 days of her period - I can't remember which. It seems a little weird to me, but then it is NOT prescribed that way for everyone.
Did your doctor switch you from a different triptan?