I've ordered these a few times and on the rare occasion, I receive a fake. I've learned how to spot them. Just read some of the other reviews about the fakes to learn what you need to look for.
The real ones are good cards but normal usage will not give you the "rated" speeds. This is true for any memory card and not just these so keep that in mind when you read about speeds not being achieved. In order to get the "rated" speeds, all the conditions have to be ideal and most users simply don't have ideal conditions.
That being said I use these in my DSLR cameras and I do shoot in burst mode often. I have found the speeds on these to be more than enough to handle a burst of fast action shots. I've not had any occasion where the card is what let me down.
I just started replacing all my 8 and 16GB SD cards for 64GB ones just so I don't have to carry as many and I like the better performance of the newer cards. I've had good results from SanDisk in the past and now with these too.
I'll buy them again. Just make sure when they arrive that they are the real deal and not a fake. If you get a fake send it back immediately and Amazon will make good on it.