I used to apprentice for a local locksmith company.
The Masterlock #-series locks are sheer pin locks. That is, in order to set the pins, you literally insert the key you want it keyed to, and sheer the pins off to the lengths that match the cuts in the key. This makes them really easy to pick already, I've gotten into one with a small paperclip, so I wouldn't even recommend them for minor things like keeping the kids out of your wifes box of dildos. They can be convenient only in a situation where you need lots of them fast (I had it down to ~20 seconds per lock).
As mentioned in the article, American Padlock (owned by MasterLock), Abus (I really like these personally), or even Guard brand padlocks are a safer bet.
The American and Abus padlocks can have the cylinder removed and recoded easily (as long as you have a key), saving you from buying a whole new lock if you simply want to keep one keyholder out for whatever reason.