There are really no direct competitors to points.com, in that the key service that points.com offers is the ability to transfer miles between otherwise unaffiliated programs. The ability to view balances is, to me, a completely secondary service that really has little to do with why points.com exists in the first place.
That said, there are other services that offer the ability to track balances, such as
www.mileagemanager.com.
Mike