USB miners is like the dumbest decision you'll ever make... They profit you literally nothing, especially with the difficulty rising quickly.
Dunno, they make amazing lottery miners. They have a different purpose than let say a S5. They fill a different niche and just like any other hardware, some sticks are great (sidehack stick 8-23GH/s+) some sticks are horrible choices (nano, 400MH/s, etc whatever).