The hardware specs are underwhelming, to say the least. This thing is about equivalent to an iPad 1.
Already preordered one, at last a fully open Linux tablet (apart from the binary graphics driver).
it might still have e.g. a binary wifi driver, not many of these are fully open either...
The Spark is a Zenthink ZT180 so the Wifi module will be a RTL8192, which afaik has open source drivers.
I'm taking a wait and see position. Eg, I'm not convinced by the UI: superposed UI elements as seen on the screenshots don't seem a good idea for a tablet.