Correct, I believe the erurorack modules support up to the 128’s.
And everyone here is right that the 512 is two 256’s with one usb and power port.
You will find it most useful if it’s easy for you to write monome applications and require (obviously) lots of LEDs/buttons to display and interact with at once (like if you already have twenty-two pages in your application and don’t need more). Now, I find my bus-powered 256 very useful for prototyping on-the-go and can keep the 512 safe in time for studio sessions/performance.
I defintely wouldn’t buy one without a specific idea on how to fill that space (and without the will/time to get your fingers dirty)
I never touched a 512, but I know from my 256 experience: having a huge array of buttons and only really using part of it is not going to make you happier. Starting right away with 512 buttons may be well overwhelming.
i sold it after a couple years(varibright changed things for me… i also found i prefer a square canvas)… played 5 good gigs with it, though
those 512s are still amazing for things like ‘game of life’ and such… varibright’s not a necessary thing… but ya, i dunno about $7k+ (for that amount maybe buy a 3d printer and you can build 512 housings endlessly for others)
oh snapz, i see linked near bottom of that page with the 512, a nice varibright 256 from 2012, listed as “Monome256 MIDI Sequencer”… haha, i don’t think that person knew what they had. it’s also going for a nice price, too(i see it’s about to be snatched up). congrats to the new owner!
this was “Serpent Eclipse” (an app i made in Max - but was too much to document back then so i never released it ), i doubt it’d work today because it required some custom max externals i coded too(for the circular led sequencers to happen more easily), but never updated for current OSes
i just tried it out, i get too many error messages(i can see from error-messages in the max window there are externals(max objects i coded in C) which are ‘unable to load due to incorrect architecture’(these were built on architectures from 2010(like intel i5, etc.)), and some of 'em i don’t even know where the source-code is anymore to rebuild with)… nothing but a set of non-functioning max-patch-abstractions now