I've got a 4" Luzon, and its not a knife for somebody who isn't afraid to do some tinkering. I also have a large Luzon and it works perfectly in all aspects. I expected the smaller one to be just as good....but......Out of the box it was not so great. The detent was way too aggressive, making the blade very hard to open. The lock face was rough and the liner lock had a weird edge on it, making it difficult to operate. The thumb studs were useless. The flipper tab was polished smooth and it was quite slippery, making it hard to use. The clip had a small hook on the inside of the bottom end, making it nearly impossible to extract from your pocket. All these thing combined to make the knife quite unsatisfactory.
That being said, its not hard to address and correct these issues. I took it apart, polished the lock face with a fine stone, stoned the detent down somewhat and made a small detent ramp on the blade, fixed the liner lock issues, filed a bit of jimping where needed, and generally cleaned things up. The knife can now be easily popped open with the flipper tab, but the thumb studs are still nearly useless, the geometry just isn't right. Five minutes with a bit of sand paper fixed the pocket clip issues, and it works fine once that hook is softened up. The lock, once the burrs on the edge are removed, is fine and operates perfectly. The blade does cut well even though the steel is not the latest and greatest, but it is after all $40 knife. It takes a good edge, is easy to sharpen, and seems to have decent geometry.
Overall, if you want a knife that you take out of the box and use, this isn't it. If you don't mind doing a little bit of work on it, it can be made so much better...