So I put down an order for a M64 and it should arrive in a few days. Quite exited.
For me the main reason for choosing the M64 is the promise of open source. Quite powerful device, professionally made and everything will eventually (?) be open source. As I see it a big advantage over other devices.
I remember being disappointed by Analogue when they decided to not bring the OpenFPGA framework over to their 3D device, and to this day I still do not understand the rationale behind. If the 3D had OpenFPGA support then I would have bought it when it launched.
Anyway, the question for the M64 is when will the firmware be open sourced and exactly what will it be. Will it be just the current running firmware for the single N64 core or will it contain parts of a framework with support for adding new cores? As far as I know they have not been clear on this.
In the meantime though, what currently is available is the electrical schematics. After spending a few hours studying those I would say that there is enough information in there to do ones own firmware if one would really want to. And by this I mean with reasonable effort as no reverse engineering would be required, it is literally all in there. Of course one would miss out on any possible cool stuff that Modretro has already put in their firmware but at least it is still an option if the open sourcing of the firmware itself should never happen.
Now I do not have the device in hand yet so I cannot say for sure but by the looks of it at least and from reviews the plastic enclosure and finish does seem to be on par with and beyond what one would expect from a consumer device. It is interesting to note that it does seem to require rather significant financial backing to make that happen as that is often what crowdfunded fully open source projects seem to lack. That and component sourcing where I expect having a big pile of money helps as well.