have been pure member (yoga & fitness) for the past 4months, and am loving every minute of it. am not sure about FF, but pure Yoga teachers are REALLY professional - some are new, but they are all certified by going through formal teacher trainings. but pure yoga classes can get really busy in the evenings. Pure fit offers yoga classes, too, which don't seem to have prenatal and it's basic generic classes.
At pure I also like the DVD on the machines, T-shirt, shorts, socks readily available in changing room shelves,apple - all complimentary.
their steam and sauna room and shower facility is pretty good, too. but their shoe locker rental costs 350! and waiting list is very long.
I would recommend you to ask them for a trial pass first. You can then experience the convenience and such.
Pure has a few pilates classes, and i have been to Geoff's during lunch hour once, he's really good.
hope someone can post FF stuffs.