I just got back from three days in the field and used this knife extensively. It was the first time I'd used it since I bought it.
The good: The knife itself performed perfectly. The blade was sharp and held its edge well. I used it on everything including brush, branches, 550 cord, food and anything else that needed cutting. It cut easily through the heavy stuff and is ergonomically designed well enough that I was able to precisely cut the inner strands of the 550 cord. Great knife. I worked it hard but I didn't abuse it. Other people have done destructive tests on it. You can Google them if you want to see the punishment it can take.
The bad: I almost didn't bring the knife back with me. The last day I was out, the sheath fell apart. The two screws attaching the Kydex to the belt loop popped out while I was walking through brush and the lower portion of the sheath holding the knife dropped off my belt. I felt it start to fall and caught it. There was no way to fix it. The screws were gone. I carried the knife (in the Kydex, of course) in my back pocket the rest of the day. If I'd been distracted and not noticed it falling, it would have been gone for good. I checked SOG's website. The warranty specifically excludes the sheath. If my experience is typical, I understand why they would. It's junk.
Some people may consider it harsh to downgrade the product two stars because of the failure of an accessory. I disagree. Reliability is the number one concern in the field or with any piece of tactical equipment. SOG failed miserably on this point. They put the SOG name on the sheath, so it represents their brand. If the sheath had failed after three years of steady use, I could understand. But three days? You've got to be kidding.