Well, it's not quite the same as having an onboard SF-2, for at least the following reasons:
1) The standard onboard filters are low-pass only, while the SF-2 also offers band and high pass.
2) The standard frequency control only goes down to 350 Hz on the instrument, while the SF-2 will go all the way down to 45 Hz (the upper limit is 6K for both).
3) The SF-2 allows you to blend the direct and filtered signals, whereas the instrument signal always goes through the filter. With a 12 dB/octave rolloff in the filter, you can't really get much back beyond the Q frequency by boosting treble (as I recall, maximum treble boost is 6 dB).
The standard onboard cutoff at 350 makes reasonable sense for a low pass filter which is always in the circuit. If my math is right, 350 is approximately the fundamental of an F played at the 10th fret on the G string, so you're already starting to lose notes if you set it that low. However, it can be useful to do so on the SF-2, even when set to low-pass, because there you have the option of mixing the direct and filtered signals, and of course a lower frequency setting can be interesting in band or high pass mode.
So you might say that the standard Series II electronics are like having one channel of an SF-2 per pickup, except they won't filter as low, won't do band or high pass, and won't give you the option to mix in the unfiltered signal (but they're still pretty amazing, of course).
Aside from all that, separate bass/treble controls for each pickup adds a lot of flexibility, without requiring a stereo preamp. Unless you really needed a tube sound or something, you could probably plug this thing straight into a power amp (with a gain control) and be very happy.
And that is a pretty piece of wood...
