I know this is a resurrected thread, and it's probably been said before, but I don't know if there really is a "best" envelope filter.
I own several filters, they're all different & I like them all. (Chunk 00Funk MkII, Chunk OS, Emma DiscumBOBulator, Tru Tron 3x, EHX Talking Machine, Russian Bassballs are my keepers). I've tried many others, and I'm still always interested in hearing new ones.
Filter's to me are a very unique type of effect, which is why I'm such a filter junkie. It takes time to me to know how best to use each filter pedal. The very same filter can react & sound very differently across different basses, they are affected by your playing dynamics, you can drastically change the sound of the filter by playing around with your volume, tone, bass and treble on your bass and/or your amp, and then how they sound combined with different effects can also vary considerably from filter to filter.
Then there are filters that are by nature very quacky, whilst others are more wet and squelchy, some are warmer & more subtle, (allowing some of the natural tone of your bass to combine with the filter effect), some more extreme (for those space laser sounds), others can be more vowel-ly or burpy (i.e., like a fomant filter).
Each unto their own is what I'm trying to say. "Best" is too subjective IMHO.