Why two 2nd order filters have different roll off?
Basically these two filters don't have the same characteristic. 


The Sallen key filter (lower circuit) has a theoretical 3dB frequency of 2340 Hz and a Q of 0.5.
The MFB filter (top circuit) has a theoretical 3dB frequency of 1489 Hz and a Q of 0.703.


Why would you expect these to look the same: -