Right now, while supplies last, Amazon is running a deal on the SanDisk Mobile Class 6 Ultra Micro SDHC 64GB card for $49.99. I have never possessed a phone allowing for an external card and thus have zero knowledge when it pertains to them. Can someone more in the know tell me if this is a decent card for the price? Will it allow for sufficient transfer speeds and decent to store my movies and photos? I see there are SDXC cards, Class 10 cards, etc. I am wondering if the difference in cost would be justified for getting a different card? IE., SanDisk 64GB Mobile Ultra MicroSDXC Class 6 Memory Card with SD Adapter $79.99 or SanDisk 64GB Mobile Ultra MicroSDXC Class 10 UHS-1 30MB/s Memory Card with SD Adapter $99.00 Thanks!!