What power of binocular is recommended for PRS competition?

I use cheap 10x bushnells to find targets when I get to a stage. If you want to spot impacts and watch trace, you will probably need to buy much more expensive glass. Otherwise my $150 binos have served me well.
 
I've been using 10x for a while and honestly have little to complain about. A friend of mine won a set of Bushnell forge 15x56 binos at a guardian match and they are amazing as well. For pure prs type usage I would go with the 15x over my 10's. The 10's seems to do better in a more field type match. 12x's may very well be the best of both worlds, it will really depend on your specific usage.