Youtube user DivKidMusic has posted this comparisson of 5 low pass filters. As he says its more of a listening test to find out which you might prefer than a full blind test.
"I have 5 low pass filters, let's do a blind test and video to show how they differ".
The AniModule - SOB, Mutable Instruments - Ripples, Erica - Polivoks VCF, Malekko / Wiard - Borg 2 and Livewire Frequensteiner. They all just have a single saw wave input.
He's also set up a user poll on the excellent Muffwiggler forum, You'll need to register to view that.
So, did you guess which was which?