Also to state the obvious QFF Silver status is not BAEC Silver -- that is equivalent to QFF Gold. Not sure that QFF Silver status is worth getting

As for earn/burn ratio, that varies with how you earn and how you burn, in general QFF is bad value but for some specific award redemptions it is great value, and of course if you get to Platinum status you have some award redemptions that are available (and not available in the cheaper FF plans as these awards are chronically sold out otherwise). Optimizing FF value is tricky, as it is run by the airlines as a profit center and not to reward you as a customer