I forgot to mention - make sure you get something no taller than 7mm (the Sabrent is 7mm).
By your comments, you're probably thinking about PCIe NVMe/AHCI which also uses the M.2 connector. These can be several times faster than SATA but cannot be used in the Mini. You can put a PCIe NVMe SSD in a Thunderbolt enclosure but with the 2011 Mini, it will be less than twice as fast and cost quite a bit of money (plus it will require use of the DisplayPort/Thunderbolt connector).