Bests & Worsts Reviews from Amazon

About a week ago, I was offered a free SanDisk 128GB microSDXC UHS-I (U3) card for Nintendo Switch via the Amazon Vine Program, and I accepted. In addition, I recently purchased a Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card, which I intend to use in my Samung Galaxy S5 phone. Since these cards are both 128GB MicroSDXC cards of the same generation and speed ratings (UHS-I (U3)), I'm going focus this review on testing the actual read/write speeds of the cards and compare the results here. MicroSDXC cards are a common storage media today used in various phones, tablets, action cameras (like GoPros) and the Nintendo Switch. I speed tested both of the cards with CrystalDiskMark 6.0.0 x64 using a Kingston Digital MobileLite G4 USB 3.0 card reader plugged into a USB 3.0 port on a Gigabyte GA-Z170X-Gaming 7 PC running Windows 10 Pro 64-bit. (See the very end of the review for the attached screen grabs of the actual CrystalDiskMark results). The SanDisk 128GB microSDXC UHS-I (U3) card for Nintendo Switch achieved it's rated 100MB/second sequential read speed, but it could not even come close to it's rated 90MB/second sequential write speed. In fact, it scored only 65MB/second sequential write speed in my tests, which is the rating they give their 64GB card. This is not a good score for this card and it indicates a potential problem with their production or their marketed speed rating. CrystalDiskMark 6.0.0 - SanDisk 128GB microSDXC UHS-I (U3) card for Nintendo Switch - SDSQXAO-128G-GN6ZA Sequential Read : 97.228 MB/s Sequential Write : 64.698 MB/s The Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card also achieved it's rated 100MB/second sequential read speed, albeit a fraction behind the SanDisk card, and it achieved it's rated 90MB/second sequential write speed. CrystalDiskMark 6.0.0 - Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card - MB-ME128GA/AM Sequential Read : 96.777 MB/s Sequential Write : 89.493 MB/s What that means to you is that you can copy or save files approximately 28% faster to the Samsung card than you could to the SanDisk card. The Samsung EVO Select 128GB MicroSDXC card is also substantially less money than the SanDisk card. As I write this review, today, December 17th, 2017, Amazon has the SanDisk 128GB microSDXC UHS-I (U3) card for Nintendo Switch for $66 versus the Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card for $37. Both of these cards will work perfectly in the Nintendo Switch. The specifications for both cards are identical, 128GB, UHS-I (U3). Both of the cards met their 100MB/s read speed rating, however only the Samsung card met it's 90MB/s write speed rating while the SanDisk card only achieved 65MB/s. I have been an Information Technology professional for over 30 years and a hobbyist before that. If you are interested in purchasing a 128GB MicroSDXC card for a Nintendo Switch (or other SDXC compatible device), this SanDisk "for Nintendo Switch" card is not the best card available. It is overpriced and underperforms when compared with the Samsung card. There is literally no reason to purchase this SanDisk card over the less expensive Samsung card. You get nothing extra with it. There is no magical extra compatibility with a Nintendo Switch. There is absolutely no benefit to be had over the less expensive Samsung card. Additionally, the 65MB/s write speed does not meet SanDisk's own specifications. For me the choice is clear, based on both price and performance, the Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card wins hands down. Update: 12/30/2017 FYI: If the Samsung EVO Select 128GB MicroSDXC UHS-I (U3) card is out of stock and only available from 3rd party sellers, I recommend that you wait to purchase it directly from Amazon, or choose a lower capacity version of the card that Amazon does have in stock. Counterfeit SD cards are a thing and you are far more likely to get the genuine article when purchased directly from Amazon. Plus, Amazon usually has a better price than the 3rd party sellers.