Have been thinking about getting one of these for a while, and last week Google Shopping sent me towards play.com for the price of 44.99 (I see it has now gone up). I ordered at 10:30pm and it was dispatched at 4am the next morning. Free delivery took three working days. Sometimes I worry if good-priced memory cards will be genuine - I normally test with CrystalDiskMark and h2testw.
Regarding compatibility, there are reports online that it works with the Nokia 808 PureView which is why I purchased it, and that you can format it to exFat which means you lose the 4GB file limitation, which sounds like good news for filming in 1080p and viewing big HD files.
Anyway, when it arrived it all looked genuine - the packaging is android-specific but it is suitable for other platforms. The packaging and the card itself have the U with the I in it which indicates the higher speed UHS-I (class 10 equivalent). This is different to what is shown on the play.com listing photo. It came formatted as exFAT but I reformatted it anyway.
The h2testw report (using the supplied SD card adapter in the internal SD slot of my laptop) was:
Warning: Only 60873 of 60874 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 11.1 MByte/s
Reading speed: 21.6 MByte/s
Since it took 3 hours to format and then run h2testw, I can't be bothered running CrystalDiskMark as well. The speeds above definitely indicate at least Class 10 equivalent performance.
Overall, I am very happy with the product.