UT, I don't really consider them all that dangerous, I just don't think that they should be the foundation of a leg program (like reg squats). I think that unless you just use them as an occasional extra exercise they will take away from your reg squat.
You just need to put in the time. Squat with no weight looking sideways at a mirror. Make sure the knees don't drift forward. Don't start a program of box squats right now, but maybe try them really light before your reg squats. They can really clean up problems with form. Set the box height so that you hit the right depth.