While much of the negative commentary concerned Levi Strauss's move away from domestic manufacturing has focused on the button-fly 501s, the bigger problem I have seen is with the old 1970's standby, the 505, which has a zipper as opposed to button fly. The variability on sizing and sew quality with the 505s is an issue if you are going to buy them online or mail order. You really have to try them on to see how they fit.
The 501 are much easier to buy online or by mail order because the sizing is much less critical on the waist, which is the so-called "anti-fit" waist, meaning there is no curve to the rise (the distance between the crotch and the top of the waist), because the original 501s were merely cut down bib overalls which were made to hang, rather than be fitted to the waist. The biggest problem I have noted on the 505's is the variability in size in the thigh area, meaning that some fit baggy and some seem rather tight, even though they are theoretically the same size of a label. Since the 501s are more forgiving as far as sizing, if you are buying online you might consider them instead of 505s, unless you don't want the button fly.
