For two months I use this card in my Pentax K-30: Perhaps could also find a slower SD sufficed, but currently 20 (32GB) grow me as not losing any sleep. The price / performance ratio is great! So far, everything is perfect and I can say to the camera no difference to SanDisk Extreme SDHC 16GB Class 10. In my estimation, no current amateur camera should be able to bring this card in speed problems. If problems arise, I will complete my review ...