Review on Sony M Series SDXC UHS-II Card 128GB V60 CL10 U3 Max Speed 277MB/S Write 150MB/S Black (SF-M128/T2) by Jeff Dabney

Works well on a7r3 for me. I don't know how it compares to a faster device that writes up to 299MB/s because I haven't tried it, but I've never experienced clutter when photographing portraits, events and nature, even in uncompressed RAW . uhs-1s were definitely slower in comparison and couldn't keep up with burst shooting even at low frame rates. If you're an extremely fast photographer and need to take dozens of burst shots over and over again, you'll probably want to compare faster cards, but for me and I think it's fast enough for most typical shooters, and about half as fast. Price.