I’ve been through several different sets of envelopes and attenuators and am thinking about switching to Maths.
Mini Slew has a neat feature set. CV control over everything, the LED indicators, and the “Vari Out” feature which is often overlooked I think. The latter is both an attenuator and a VCA; you can run a bipolar signal (such as audio) into Vari CV and the envelope will control its level.
But: the response and range on the knobs feels really unnatural and twitchy compared to most other function generators and envelopes. There’s a very small area of knob turn where the most musical results are, and a lot of area that just won’t be used.
Also, the envelope won’t retrigger during the fall stage unless the trigger is above… I think it’s about 6.5V? CV.OCD sends 5V triggers, so I have to amplify them if I want to trigger every time. It’s almost a cool feature but that threshold should have been lower for compatibility, or there could have been separate trigger/retrigger inputs, or something.
I often find EOR/EOC confusing on Mini Slew because unlike on Make Noise modules, they are not opposites. EOC is high when the output voltage is above 3V and back off at 0V; EOR is high when the input voltage is 0V or the module is not in the fall stage.
And the “T-COMP” and “CV SUM” features have always been pretty useless IMHO.
And its power consumption is well above Function.
Function, for contrast, has really nice knob response, feel and ranges whether you’re using it for envelopes or audio rate cycling. The Hang input is kind of nifty (but honestly I’d prefer a Cycle gate). But I could really wish it had an attenuverter, or at least an attenuator.
Rampage has some nice features – I preferred its Rising/Falling gates to EOR/EOC, I liked its comparator and appreciated its manual trigger buttons. But I didn’t like the rate switch because you couldn’t simultaneously have a snappy attack and a long decay, and the sliders didn’t feel as good to me as Make Noise’s knobs. Also it had some impedance problems with passive LPGs. I wound up selling mine.
Pittsburgh Envelope was nearly as good as Function, if a little homely. I just had too many envelopes and sold it.
(For non-slew envelopes: Contour is my favorite, though I wish for a cycle button and/or a manual trigger and an attenuator. System X ADSR was decent if basic, and as snappy as they say. Qu-Bit EON was better as an envelope than for its other functions, if you don’t mind working with a tiny module.)
And for attenuverter/offsets:
3x MIA is always bipolar and difficult to zero, so it makes a poor audio mixer. The knobs are really glossy and the pointers can be hard to see due to glare. Also, high power consumption. I sold mine.
321 has a decent feature set, but tiny black knobs and tinier black switches on a black panel drive me a little crazy. I haven’t found the dual mix outputs that useful. It’s kind of my last resort attenuator/mixer.
Shades is great. No complaints at all 
A-138-m counts too since its first row can be normalled to +5V. Matrix mixers are great for a lot of things. Having a constant voltage offset in an audio feedback loop to encourage clipping is pretty neat.
Anyway. After recently watching Loopop’s video on Maths I kind of want to trade my Function, Mini Slew and 321 in on one. It just seems friendlier to patch than separate function generators and attenuverters, and has the built in sum/or I miss from Rampage (though no A/B comparator or rising/falling gates) and draws less power than the three modules combined 