I wouldn't consider them at all. They're not going to offer as much noise blocking as a pair of electronic head gear. And decent head gear isn't very expensive these days. You can get very good to excellent hearing protection for well under $50.
I much prefer electronic hearing protection.
Here's a link to a few choices at Sportsman's Guide
Electronic ear protection: | Sportsman's Guide
The Caldwell muffs: Caldwell E-Max Electronic Earmuffs, Standard - 201336, Hearing Protection at Sportsman's Guide
I wear Caldwell ear muffs. They work extremely well. I shoot a 50 BMG rifle and have never had my ears ringing from the shots with the 50 with those muffs on.