If you want in-ear protection; i've used the Earmor M20. They work, don't cause your ears/side of the head to get hot but at the same time, you can still got shot in the ear which sucks. Can pick these ones up on ebay for about £40 new.
If you want over-ear, i've used the Earmor M31. Again, they work. They protect your ears but your head/ears tends to get hot.
As a note for both Earmor offerings; they don't go completely silent when they detect loud noises. The best way I can describe is that they cut out all of the top end so you can hear the 'loud' noise but at a safe volume level. In comparison, I have an unbranded headset (comtac knock offs) that cut all sound completely (depending on how loud it is) and fades sound back in afterwards.