I have the Moog 101 LPF and WMD Super Fatman (although I recommend the "WMD Fatman" without the super). I prefer the WMD for my envelpe needs and the Moog for tone shaping. The envelope sounds in the Moog are sub-par because the resonance can't go up high enough without losing low end. While there is a "Mix" knob to let you dial in the clean sound the knobs are interactive and no matter what I do I can't dial in the "wet" sound that is usable on bass. I used to own the MXR M-82 bass envelope and sold it in the classifieds. The MXR has a relatively dry band pass sound and the only way to get it "wetter" was to dial in my jazz bass to both pickups dimed, which I don't like while the effect is off. What I do like is the low pass envelope filter sound. I can get the LPF sound out of the Fatman and while it is not "wet" per se, it is very bubbly which sounds really cool in the tunes I use it for. The greatest factor in any envelope filter is the expression pedal, IMO the most important part. I usually have the expression pedal controlling the cut-off frequency.
I apologize for my scatterbrain rambling.
I have the 3Leaf GR2 on the list of filters to try and it is seems easy to use (the WMD is very versatile and is NOT easy to use).