I bought one pair of 501 Shrink-to-fit jeans in Taupe Rigid to see if they would work out.  I got lucky on the size - I ordered one full size larger in the waist than I would do with pre-shrunk jeans and went with the same inseam (which on pre-shrunk jeans is borderline too long on me, I am kinda in-between 32 and 30 on inseam; I went with 32 on these, and they are perfect after shrinkage now).  I have worn and machine-washed and machine-dried 3 or 4 times, and they are just about perfect now.  Like others have said, they arrive new and stiff as a board.  The first wash-and-dry shrinks them and really softens them up.  Now that they have been washed a couple of times, they fit well (still a tad loose in the waist, but that's better than too tight).

I LOVE the Taupe Rigid color.  It is just perfect to wear at my office - not blue jeans, but not lame Docker's type material either.  The taupe color is a medium grayish-brown.  It's the color of a wet concrete sidewalk, if that makes sense.  Goes with all of my pique polo shirts in any color.

I have now also bought a second Taupe Rigid STF pair and a pair in Silver Rigid.  All three pairs fit about the same after a few washes, which is exactly what I wanted.  The Silver color isn't quite as good (for me) as the Taupe, because it has just a hint of blue in it.  It is a little darker than in the photo on Amazon (but will probably fade to a lighter color like the one in the Amazon photo over time).  The Silver is fine though, and a nice alternate color to have for the office.  The Taupe just rocks, though - my new favorite jeans.

The "Shrink" in Shrink-to-fit is real, but it wasn't as radical for me as it seems to have been for others.  YMMV, and be sure to know whether you are buying a pair of Shrink-To-Fit (will have "Rigid" and/or STF in the name) or pre-shrunk 501's.  If you get a pair of these 501's to Shrink-To-Fit, and fit like you want after shrinkage, they are Jeans Paradise.  They are 5 stars if you get the right size, but I rated them 4 stars here because finding the right size to buy the first pair in involves a little guessing and estimating.  If you are not willing to take a little risk on sizes, stick to pre-shrunk 501's or other Levi's pre-shrunk versions like 505's, etc. The range of colors offered in these 501's is great, though.

Amazon should really consider separating this listing into two separate product listings - one for PRE-SHRUNK 501's and one for SHRINK-TO-FIT 501's.  They are really two different products that share the same code number.