This pickup is terrific if you're looking for a natural warm nylon string sound. It can be used straight into a guitar amp for a pretty good sound but is even better if you use a good preamp into an "acoustic amp" or PA. The sound is so much more pleasing than undersaddle piezos - no "quack" and a very even response.
It is a bit delicate, so if you're the type who bangs their gear around, you're going to break this pickup. But if you baby your gear (like me), you should get long and satisfying use from it. They're so inexpensive and sound so good, I'll probably buy a spare anyway.
Installation is dirt-simple; just loosen the strings till they're totally slack, then slide the pickup under the loops at the tie bar. Make sure the pickup is under all the loops and lying flat on the tie bar, then retune. You're done.
I've been trying for years to get an amplified sound I like out of a nylon string guitar without having to hack up the guitar somehow. This little thing does it!