hi …
as the author of these… first can I say these are only possible due to the huge generosity of Olivier at Mutable Instruments, in making his source code open source - I think its very important to recognise this. a huge thank you for this.
as mentioned by @mokomo , I was also also responsible for bringing some of these modules to Axoloti, Johannes and I shared the effort, I concentrated mainly on Elements and Clouds 
In time I will also be making these externals available on PC/Mac, and also Bela/rPi, and open sourcing, with help files etc. at the moment, Ive held back, to focus on getting the dev done and also while I ‘refine’ the interface.
I have to say I do enjoy them on Organelle, as its nice to develop ‘full patches’ for use, whilst Axoloti I also really enjoy, as it promotes a more modular/patch it yourself mentality… so both have a great place.
Ive a couple of Axoloti, one of which almost permanently runs clouds and some midi ‘utilities’, this is now often connect to my Organelle (which I only got a couple of weeks back)
so on to some points raised:
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Modulation
the heart of the patches Ive released are a set of pure data externals, so you can build your own patches with whatever modulation you require, PD is after all a ‘digital modular’ … so these are at least as flexible as the eurorack , and in many ways more… as you don’t have physical limitations, and sometimes more options from the underlying code are exposed
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"Sonically similar’
yes, this is a good way to put it… at the heart the code is identical to the eurorack modules (at least on ARM)… however the hardware does come into it. the eurorack module use a particular chip (stm32f4 often), which is limited in power but is 100% dedicated to that task. Axoloti is closest to this but not identical (since often you want to run other code too) , Bela is quite close as it also have real time and tiny audio buffers - and then other platforms tend to be larger buffers. Also the native sample rate can different (depending on MI module, as they are each different)
of course, though, the proof is in the sound… and on all platforms Ive found them pretty good, perhaps with some small limitations on some platforms.
so yes they are sonically similar, but I would not claim identical
of course, I also hope, for those lucky enough to have a eurorack system, if you use these modules, then perhaps you will be encouraged to buy the MI eurorack modules, perhaps it’ll even convince a few to get into eurorack