Great for the range during qualification. I can hear all the students and ambient noise without the report. I occasionally use plugs when I just go out to pop a few rounds and the difference is night and day. The muffs work so much better. I find it interesting that even though I can hear ambient noises and voices great (even better if turned up) I still sound like I have my head in a bucket when I talk. While a little annoying it helps me remember to talk louder on the range for the benefit of those without amplified muffs.
I have not noticed any static unless turned up to the highest setting. It surprises me sometimes when I have them turned up higher that I start wondering what that background noise is only to figure out it's the breeze in the power lines or the milo rustling across the road. That's a good indication to turn them down.
This is also just for pistol use outdoors. If I am going to be shooting high power rifles for an extended session I use plugs in addition.