MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
In the Klipper documentation on GitHub https://github.com/KevinOConnor/klipper/blob/master/docs/Features.md is the following description:
"Klipper supports printers with multiple micro-controllers. For example, one micro-controller could be used to control an extruder, while another controls the printer's heaters, while a third controls the rest of the printer. The Klipper host software implements clock synchronization to account for clock drift between micro-controllers. No special code is needed to enable multiple micro-controllers - it just requires a few extra lines in the config file."
I simply decided to go for it as I love this kind of flexibility. The print results in combination with the performance are excellent. The speed limit depends only from melting the filament in the appropriate time and not from the AVR´s in that combination.
I'm sure a single board would also be ok but my feeling is there will be some limitations by the AVR.