Re: "At MWC SanDisk was showing 400GB microSDXC memory cards with speeds up "
I had one of these micr SDX cards fail on me a little while ago.
The exact reason Sandisk is not a popular brand in this family. Their sd cards tend to have some "interesting" failure modes. There is never any gradual deterioration. It just suddenly starts reporting itself as zero GB in size and this is the end of the line. So if I have a choice I will chose Samsung - it has shown itself to be significantly more reliable including working in some of the razzies and bananas I have out in the sticks which remained operational from -27C ambient to +45C. It just kept on ticking.
Biting the hand that feeds IT
