interesting

ok I just finished building a case - they are not a lot cheaper - the expensive bits are the rails and the power - 9u/84hp costs me a bit more than 200€ (rails, threaded nuts and power) and a 9u/104hp costs about 100 more (needs extra power and I tend to use inserts not nuts) - of which the wood for the case is about 10€ - the bigger the case you build the more you save!

I would go for a 6u / 104hp case - the 1u row costs as much as a 3u row to install and can hold no where near the functionality

vcas are one of those things - you only know you have too few when you run out - depends entirely on how you patch - some people use no vcas - some use 10 per voice

you already have an envelope generator - Maths - although maybe a basic adsr one is a good idea if you are intending to use a keyboard

why is veils better than a cloned version - in this case it was cost - 1 veils is cheaper than 2 of the 2 channel clones

the mutable clones should sound the same and use the same (or extremely similar components) BOM and firmware are publically available as appropriate for all modules (probably not beads yet) - I can't comment on build quality (and it may differ wildly)

in general clones (and we're really just talking Mutable Instruments here) are less ergonomic - as they have been shrunk - this may be seen as an advantage if you are in the cram as much as possible into as small a case as possible crowd - or you only have a few hp left in your case (time to get a new one - you did start saving as soon as you got the previous case, didn't you?)

size is really the only excuse for buying clones - mostly they don't save that much money - maybe 50 €/$/£ or so - which in the big scheme of things is not a great deal - especially when looking at a case that costs 4k to fill - maybe it helps to think of it as - Hi Emilie, thanks for creating this fantastic module that i will use for many many hours and get great enjoyment from - here's a few glasses of chardonnay to celebrate - or whatever it is that she likes to drink

really if comes down to where you want your money, that you earned, to go:

do you want it to go to the original designer? - thanks for putting in the hard work

or to some guy who worked out how to make the pcb a bit smaller and order pcbas and panels from China

remember MI are built in France - a first world country - where wages and taxes are significantly higher than in China

utilities - I have no idea either - it really depends on you and how you patch - when planning a rack I usually try to think:

sound sources < sound modifiers < modulation sources < utilities

as a single sound source can be multed to multiple sound modifiers and used with different vcas and envelopes to create different timbres and rhythms which then need mixing

or it may have multiple outputs that can be mixed before being sent to a single filter/vca etc

or you may have more modulation inputs than outputs - mult the outputs, modify them and mix them using utility modules before sending them to the inputs - lots of related but different modulation - for relatively little cost

it must be noted that a sound source in this case could be multiple vcos, sound modifiers could be multi-channel and multi-purpose, modulation sources could be multi-channel etc etc etc

as a starter set of utilities - links, kinks, veils and shades cover a lot of territory in not that much space, you get:

2 buffered mults - useful for copying v/oct signals (anything else won't notice a bit of droop so use passives) one of which can also be used as a 2channel mixer or a precision adder (for transposition)
a 3 way mixer
a rectifier - this modifies a waveform by inverting all of it, inverting just the negative portion, or setting the negative portion to 0
basic logic - send 2 gates in get and and or out
sample and hold - send a trigger in to freeze the input at the output - send a copy of a sequence to this with a different gate pattern than the original to create a 2nd melody line - add these 2 together using a precision adder to get a 3rd, higher note
noise - a noise generator that is normalised to the sample and hold input
4 channels of vca - which are actually amplifiers and not attenuators! which can be mixed together - no idea what else - only got an original
a 3 channel attenuverting mixer that can be used as a precision adder and can generate an offset

that is hard to beat in 24hp - it is almost definite that you will need all these functions sooner or later

"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia

Utility modules are the dull polish that makes the shiny modules actually shine!!!

sound sources < sound modifiers < modulation sources < utilities