But... why USB? you won't get any performance from the SSD at all (yes it is possible to have SSD USB, contrary to
@Digerati 's believes but it is more like a DIY kit)
If you are using a desktop and still having a PCIe Slot left, buy a PCIe card for M.2 ssds and enjoy.
If you are talking about USB for normal usage then
Sandisk Ultra Fit will serve you best (yep supports USB 3.0 so you can enjoy the extra performance)