Like I said, I swear by Spinrite. I use it extensively and am still surprised at how well it works. That being said, it's not a data recovery program like Recuva. I recently used it on a bunch of SSD's (level 2 mode, never any higher on an SSD with SpinRite) that were showing some signs of slowing down. Worked great. And yes, it will work on USB sticks/drives as well.
I don't know how SR works exactly, but I can tell you this - I've had it bring seemingly dead drives back to life long enough to pull the full contents off the drives before all was lost, and it paid for itself in the first week I had it. I've likely used it on well over 100 drives over the years and with the exception of the one time I had to put a very mangled drive in the freezer while SR was running, it's worked flawlessly for me. I use it so often I have a copy on USB key and CD right beside my Lian Li PC-T60B test bench machine.
Even had it bring my old 1 TB drive that croaked in my SAM when I first got it back to life.
Warning: SpinRite is slow. Very slow. I'm extremely happy with it, though. Some people have differing opinions, and that's why GRC has a 30 day money back guarantee on it.