As for having a good locking folder, the KaBar Dozier you selected looks like it would be a very good knife. A Spyderco Delica would be another good knife to consider, roughly the same weight as the Dozier but with better steel imo, AUS-8A vs VG-10 and that Delica is flat ground. There are so many...

Either would be good to drop in your pocket, but for just opening boxes and cutting cardboard, a folder with disposable/replaceable blades is my preference. Iíve got the Husky shown above.

Edit: Just noted the price point - $21.38 on Amazon; that makes the Dozier very compelling. Still, $7.88 for the Husky at HD with 10 replacement blades.