Maths Channels 1 and 4 are very useful for me , efficient ,snappy etc. a lot of tricks and ways to use it , west coast style .I didnt like the results i had with it as an enveloppe follower and it is a bit large if i need only one channel . May get another one channel Serge inspired function generator instead( After Later Audio Tilt maybe) if i find a report of compared efficiency with Maths. Well , size was the motive to let go of the QMMD , which i can of regret so...
But i have to mention the WMD Multimode Enveloppe , (have 2 ,one with expander for CV and pulse out for all stages) It is not an easy one at first as controls on Attack, Decay and release are the opposite way of "usual" enveloppes : longer time =lower RATE so CCW on the pot... Also the modes pot is not incremented and has no less than 9 different modes from AR to ADAR cy. (!) So these are the drawbacks but you have shape for A ,D,R from expo to log thru linear, 0 to 8V out. -8 to +8V out and inverse +8 to -8V . and that can be very useful , especially with a bipolar VCA like its excellent counterpart the WMD Multimode VCA (double channel) which is a very clean VCA with huge headroom (theres a built in saturation helper if needed though)and Fade /Pan functions , AM with ring mod feel , Expo or linear modes with all the outputs you'd need , A , B , sum and inversed ones.
The MMEnv -8 to 8V also gives good punch with some filters i have , even though the CV ins in those should only react to positive voltages i guess, maybe the little delay involved in the stages when going from neg to pos voltages . Anyhow , going bipolar does not reduce the voltage by half as its usually the case , it uses the symmetric PSU capabilities to the max , as does the headroom on the MMVCA . Check out their specs , they are awesome