Actually, it’s very good! One of the hardest things to do when working at this level is to write the boot loader and Olivier has recently released this as open source too. That is a massive leap forward for anyone wanting to develop using this technology.
At this point you suddenly realise that you effectively have a hardware interface that takes care of all the hardware IO, knobs, LEDs etc, so the only thing left to do is imagine what you want to do and start writing your DSP code.
The DAC is appparently very good, although I don’t really know much about this, just trust the folk who say it.
For a mere £190 I think this is extraordinary and one of the best platforms available to start developing your own stuff in.
Of course you may find that the IO configuration isn’t to your liking, but again, because it’s all open source, I don’t want to say it’s easy, of course it’s not, but it’s not that much of a leap to repurpose things, hence the emergence of things like o_C.
Likewise, just my opinion
p.s. there’s a great tutorial from Tom Whitwell that walks you through the basics. In short, buy an STM32 programmer (£6) install the image of Olivier’s development environment as a virtual machine on your computer, and erm… go!