This looks fun. I'm a bit surprised that they went with the Arduino "standard" with its weirdly spaced headers given that I assume that most of the Arduino software won't run on the chip. Or did they make a compatible SDK?

Also looking at the specs it seems that the SoC has PWM, UART and QSPI but no I2C or DAC/ADC. That might make it a bit annoying to port some Arduino designs to it (although you can always bitbang the I2C). There's also no USB or MAC unless I missed something. So basically if you want to get data in and out fast QSPI is your best bet and even that doesn't seem to have a DMA so you'll have to use CPU cycles to copy everything in and out.

So in summary it's definitely a cool board if you're interesting in hacking on RISC-V specifically but if you're just looking for a controller for your next DIY project there are more fully-featured options for cheaper.