With a price like that it almost sounds like a case of too good to be true.
Swanson uses BO from Argentinian cattle, so it's safe from mad cow.
The one you linked to doesn't actually list the source of the cattle, so use at your own risk.
Swanson doesn't list any kind of extract ratio, so it makes comparing them tricky.
The daily dosage for yours is 3/day(I'm assuming that's the female dose), the Swanson says 1/day(adult female), which leads me to believe the Swanson BO is actually stronger. Maybe I'm wrong.
The Swanson BO doesn't have fillers.
The other brand has vitamin E,calcium, and black cohosh.