I don't think it makes much of a difference. I use both the translucent plastic milk jugs, and clear soda bottles, green soda bottles and they all seem to work as well as the other.JMHO

I'm brand new, so I have no results to share - but I do remember reading somewhere in the FAQ on this site or the wintersown.org site that if you can see your thumb through the plastic, then it's OK. I'm not sure if more or less opacity has any effect on success though, if clear vs. cloudy will have different results. My guess would be that if it does make a difference, it is likely the result of multiple factors including direct light in your location. ie cloudy plastic may have better results in areas with a lot of direct sunlight, while clear plastic may be better in low-light areas. That is just a guess though. Good luck!
Sherri

Cloudy might even be better for all I know. I'm using a lot of clear this year but my first year WS'ing was only in 1 gal milk jugs which are translucent, and it worked fine for the ones I got and in mostly shade to boot.