I just received one last week. I haven't had much time to use it, but I wanted to address two things.
1. You cannot adjust the angles, but it does come with TWO guides. One is for 15 degrees and the other for 20 degrees. It looks like you could easily make guides from plastic rod stock to any angle you want.
2. Although you cannot see the tip, it doesn't take but a few minutes practice to keep from running it off the rod. CRKT's instructions say to stop short of the tip and then go back and use tiny strokes to sharpen just the tip. That seems to work.
I have an old, grubby, and very dull Gerber Halsey Air Ranger that I want to use as a test. I'll report more when I have a chance to really sit down and use it.
Mark