Unfortunately I don't think Spyderco has mastered making a strong plastic clip.

Their metal clips, though, work very well for me. My EDC for a long time has been a Byrd Meadowlark, and the clip is as strong and tight as the day I got it. I wear this knife clipped to my waistband behind my right front pocket, with most of the clip hidden by my belt. For an inexpensive EDC folder, it's hard for me to imagine beating the Meadowlark.