Performance is unremarkable. You can hear the riccochets pretty frequently, accuracy is generally crappy, and terminal ballistics are intermittent at best. They work, but, basically, you get a rifle with the 'splatter factor' and accuracy (and therefore limited range) of a 22lr, but with a lot more noise and heat.
For the tiny price difference between white box hollowpoints (or better yet, handloads), it's really a no-brainer.