Not too familiar with the ones in your pictures. However, things I would be looking for in a shield are:
* A proper fit that is flush with the face of your lock
* Heavy metal
* Two solid screws
* Steeply angled sides so wrenches have a harder time getting a hold
* Possibly bearings that allow the outer edge to spin if the protector is turned with a wrench
I would avoid:
* Improper fit that allows the face of the lock to stick out the front
* Thin or soft metals
* Thin or weak screws
Also noticed that the protector in the left picture has a spinning shield for the keyway. Good idea, but be sure your key can still reach the face of the lock fully without the shoulder or bow of the key being stopped by the shield. If needed, you may need to trim the shoulder it notch the key bow. Proper function of the lock an key comes first!!!
Also look at door jamb reinforcement. A protector for the lock cylinder does no good if the door can be easily kicked in.
Good luck, and look forward to the input from other members here, as well as what you eventually choose to install.
Gordon
Just when you finally think you have learned it all, that is when you learn that you don't know anything yet.
