I found the EP-3's to be more comfortable than the EP-4's. I've had half a dozen sets of EP-3's over the last year or so, and they're great. I got the EP-4's a couple of months ago since they're supposed to offer better sound attenuation, and they get uncomfortable faster. They do block sound a little better though.
"We sleep safely in our beds because rough men stand ready in the night to visit violence upon those who would do us harm." -George Orwell
"One hundred rounds do not constitute firepower. One hit contitutes firepower." -Gen. Merritt Edson, USMC