Perfect for Bass
I'm primarily a bass player and I use these picks with great success, even on a five string. Obviously they work great on guitar too. For me they are just the right thickness to get that sharp attack on the bass while still being thin enough for speed rhythm lines and over all fast playing styles.
I play speed metal, thrash metal, and death metal and they work great for that. As such they should work great for everything else in between too. These are textured picks so be aware of that if you prefer smooth picks. These won't slip or slide from between your fingers, but they can be a bit difficult to manipulate if your the type of player that likes to spin the pick around to play with different sides of it.
For me these are the best picks I've uses yet on bass and are a great all around pick for electric and acoustic guitar too. I highly recommend them.