Figure 85 shows the comparative response curves for each of the filter design examples. Both filters hit the desired response shape exactly. However, notice the loss of stop-band rejection in the Sallen-Key design. This loss results from the op amp output impedance increasing at higher frequencies and allowing the signal to feed through the feedback capacitor to the output.
Figure 86 shows a comparison of the output spot noise for the two designs. The Sallen-Key is much lower because of the lower resistor values used. Also, the MFB shows a noise gain of 2 V/V versus the Sallen-Key gain of 1 V/V. This difference immediately increases the MFB output noise by at least twice the input voltage noise from the op amp. The higher resistor values also increase the total output noise for the MFB.