They don't cost $40, duh. There's definitely grades of nylons. I have MKS ones which are really thick, and I have no problems whatsoever. I've snapped cheaper leather straps before, and wasn't someone on here just reporting that they recently snapped a Toshi?

As far as the clips - how would that affect things at all? All the clip does is hold the strap open and provide a guide for your toe (right?); the strap does the work which is why some brave souls rock straps without clips...