Pros: 1) Anti-rattle bolt works well to reduce rattling of the bike rack. 2) Easy to use. I can install my bike rack with this hitch pin in under 5 minutes. Lock just pushes onto the bolt without needing to insert or twist the key. 3) Detent on bolt also works with some clips if there are times you don't want to use the actual lock and want to use a clip instead.
Con: 1) Bolt extends beyond hitch a bit depending on the size of your receiver. A determined thief with a bolt cutter can cut it with some effort. 2) Lock cylinder itself is easy to defeat. I am a novice lock picking enthusiast and can pick the lock in under 10 seconds. The push-on design also makes it technically shimmable. 3) The biggest con is that the keys are the same for all the locks of the same model. I bought 2 locks, one for me and one for a gift and the keys are interchangable.
Although the list on cons might sound bad, you gotta realize that all locks have security flaws. If a thief is determined enough to steal your bike rack, he or she will find a way. Your average unequipped hoodlum most likely won't be carrying a wrench, bolt cutter, lock picks, same key. Overall, I think this is secure enough if you need to keep your rack and bikes unattended for short periods but I would recommend adding a strong cable lock to lock your bikes, rack and hitch all together if you plan on leaving them unattended for longer periods in a sketchy area.