To put it a bit more in context: Fb1 is a pseudo ugen, a compound structure built on native SC UGens. It might result in a high number of basic UGens (can be hundreds or even thousands). This doesn’t necessarily mean a high CPU usage while running, but might result in a relatively long SynthDef compile time.
If applicable, as in the example given in this thread, I agree, FOS / SOS (or LTI from SC-plugins in the case of linear filters of arbitrary length, but with fixed coefficients) are a quick and easy solution and likely to be less CPU-costly.
On the other hand, Fb1 provides options that are out of their scope: larger lookback-depths with varying coefficients, varying lookback-depths, arbitrary non-linear operations, multichannel feedback / feedforward with cross-channel relations etc.
That’s where, I find, the experimental fun starts, for straight linear filters there exist the aforementioned other classes (and for special non-linear filters there exist dedicated classes too, like NL from the SC-plugins). Two related threads:
TPT filter with Fb1:
On filters in general: