I used my PRO17's for the first time atlast weekend's gigs.
They were incredible - I'm used to the usual basic earplugs, and these are a different league. Amazing flat response. You can hear people talking quietly in the room, but they seem to kick in at volume. I have no idea how they do it.
And.. singing doesn't feel weird and boomy. That occlusion reduction really works.
I completely recommend getting them via the musicians' hearing scheme I mentioned above. £40 is a complete bargain.