Firstly, tested through to ensure no bad sectors, tested as 32GB and formatted as 29.8GB so all fine there.
Speed wise using HwTest2 and Crystal Diskmark, writes at 11.1MB/s and reads at 18.5MB/s through usb 2.0 and the enclosed card reader. This means it's a definite class 10 and as HD video is 1080p at 3.5MB/s then playback etc. will be fine.
remember that smaller files are never written as quickly as larger files using flash memory so MP3's pictures and HD movies will be fine but tiny 4k files will seem very slow. I have had other cards that aren't as slow as this for small files but they weren't as fast at larger files. most of what this will be used for is larger files.
At 32gb sizes, class 10 is really a minimum reuqirement simply due to the amount of time it would otherwise take to load onto the card.
Works perfectly in my Xperia play, and the pinch point is usually the handset rather than the card when this quick.
There are faster cards but for what this is going to be used for (carrying games, picures, and recording video on) this is fine.
very impressed for the price, and mymemory were ok despite being a bit rude about their claimed 10% paypal discount not being honoured, but that's mymemory, not the card itself!