This does read like a pure PR piece. TE angered most of its fanbase by increasing the price of the OP-1 after it claimed parts became more expensive due to a new supplier.
[1] https://github.com/hundredrabbits/Orca [2] https://github.com/digego/extempore
Theres also the sonicware elz1 but it looks to be focused on being a synth.
For the music hackers out there I'd recommend checking out the Critter and Guitari Organelle M as a more budget (<$500us) and FOSS friendly alternative. The new organelle M has a Raspberry PI compute module under the hood.
(The "ultra-budget portable" option is to get a Casio SA and a digital FX pedal. Combine that with a line-in to a DAW setup, and a lo-fi instrumental album is totally within reach.)