Seriously though, any tips? I think the shield is super fun but I never get more than a couple kills with it.
If you're playing Core, don't expect to get kills with the shield unless the person's AFK. Heck, don't even expect the shield to block bullets, because unless the enemy's across the map, it doesn't. Especially against shotguns - if one pellet hits your foot, it counts as every pellet hitting.
To get kills with the shield, play Hardcore. Equip C4 and use that to kill people around corners, and use whatever secondary you want to kill other people. Only use the shield to melee unsuspecting enemies, and to block bullets from people across the map. Otherwise, the enemy will just use lag compensation to strafe around you and shoot you before it even shows them strafing.
So basically, don't rely on it to shield you. Only melee people in Hardcore, and only do it if they don't see you. Otherwise, you'll just get shot.
And beware the people who know the shield's weakness - the knife. If an enemy doesn't shoot at your shield, he has the advantage. All he has to do is just run up to you and knife you. He can knife right through the shield.