Because of market competition, you won't go wrong most of the time if you go by price as a guide to quality when buying tools. If you're pondering whether to buy the $100 or $200 tool, go with the more expensive. Quality tools are a joy to work with and, properly adjusted, they will produce superior results. Also, it's less expensive to buy a quality tool the first time than to replace a lesser tool with a better one later on.
When installing a new or replacement lock, be sure the keyway is positioned so that the cuts of the key will be inserted upward. This will reduce the chance of dirt, dust, and water (which can turn to ice in cold weather) settling in the lock mechanism creating a lockout or stiff operation of the cylinder.