I suppose any differance in weight would be more noticable in longer lengths.I have Canons,Stihl ESs, Oregons Powermatches and reduced weights, and some Carlton Branded bars. The Canon's (and WP) I have are much heavier than any of the others. I've actually quit buying Canons mostly because of the extra weight, especially my 36 inchers. Great bars, though.
I also should have qualified my statement by saying I was speaking of 20 and 24" bars that I commonly use.