[lstar337]

Yes, regarding Sandisk there ar different version, all class 10, but with different prices and different performance (some of them mostly aimed to DSLR burst shooter or video makers).
I have a microsd sandisk extreme that when put in the mbp card reader (that is connected by usb3) writes at 45 mB/s It's pricey but Amazon.it had a very good price for it, and at that time I was using it as additional storage on my Surface Pro so wanted something performing
Also @droidelec when tried to copy some stuff on that card was surprised by its speed, lol

Well the one I bought said:
Upto 80MB/s read, 533x on the packaging, along with

SanDisk Ultra microSDHC/microSDXC UHS-I cards are a great choice for Android-powered and other smartphones and tablets. With SanDisk Ultra microSD UHS-I cards you’ll benefit from faster downloads, higher capacity, and better performance to capture and store up to 128GB of high quality pictures and Full HD video.

I don't think it made a mention of write speeds. Yes it wasn't expensive, but tbh I didn't know there were different types within the classes. And why would they do that? Surely it just makes it harder to compare and buy the right one for your application?

Since it does seem to make a performance difference, maybe we should think about creating a list of recommended cards and part numbers so people can order them correctly?