Myself, I usually avoid any open box items as they probably indicate potential issues. PSUs and Motherboards especially, as if someone bought it and tried to get it mining and failed, they might have simply sent it back. Now NewEgg doing a basic testing might now be selling it as Open Box. I think they are only $69 normally, so you saved $19, I wish you the best of luck with it.
Newegg does a good job with open box items and I have personally never had any major issues with their open box items. Most of the reviews are just from newbies who don't know how to setup a mining rig properly, and any savings are good when you're mining. 30 days is usually enough to expose any major issues with a motherboard anyways, so I feel the savings are justifiable for an open box item.