Finally arrived yesterday I got the 4GB, waiting for 42mm M.2 SSD on backorder everywhere if you want a reliable one. I could get Transcend, Adata or some Chinese brand I never heard of, but lots of reports of failures with them. I have 32 GB MyDigitalSSD on order that might be in stock 3/30 and 128 GB that might arrive April 4 I have good experience with their mSATA hopefully applies to M.2
I’ll try with Micro SD this weekend I spent a fair amount of time testing different ones for random read and write performance. I think SanDisk Extreme PLUS gave the best results followed by Samsung EVO (regular) most seem optimized for sequential writes for use in cameras not random. Relatively speaking they mostly seem comparable to USB 2 flash drive or worse unless you’re accessing sequentially.
Firefly vs pine64 they appear to be more organized with the software vs with pine64 took months for a lot of the hardware to even be supported, but will see when I actually test it. I’m not seeing as much community involvement so far at least on non-Chinese discussions.