EDITS 9-26-2012: I wrote my original review (below) when I researched my pending order of 6 cabinets (60-drawer) and some dividers, but before receiving the shipment. I can now report from items in-hand. The transparency issue is probably not going to be a problem for most uses, but there are other changes from the older product that may be important to you.
The drawer material is polypropylene and is just like that used in most clear storage bins or the non-disposable food storage containers that we see all the time in grocery and department stores. It is the same thickness as the old drawers, about .036" (as thick as 9 sheets of paper), which is thin enough to look pretty clear.
However, whereas the old drawers had locations for inserting 3 dividers into each one (I can only report on the small drawers I'm using), the new ones have just one, at midway. (I intend to use clear hot glue, which is one of the few common adhesives that will stick sorta OK to polypropylene, for the places where I need different divisions.) The dividers themselves, purchased separately, are still polystyrene. Be careful when snapping them apart from each other as-shipped, since they break easily when doing this.
It seems that the cabinets have been modified for the new materials and assembly used now. Possibly because the new drawers are more flexible than the old polystyrene ones, the drawer-stop tab protruding down from the top of each drawer opening is longer now (1/4") to catch the drawer better, I'd guess, as it is pulled out, but is much more likely to interfere with drawer contents when opening or closing a drawer that is pretty full to the top. It's such a pain in my case that I cut all 360 of them off, not caring that drawers can easily pull all the way out. However, they use the tab on the cabinet and not on the back of the drawer because it not only stops the drawer from coming out too far, but also stops it from going in too far. They otherwise would have had to provide a separate stop or panel at the back of the cabinet, and there is no back panel: The cabinet is mostly open at the back (much lower mfg cost). I used 1/4" foam core to make my own back-panels, btw, a hassle, but I'll eventually get over it, and will from now-on be able to open and close drawers that are full!
The cabinets used to have a reinforcing frame at the back that went around the entire perimeter. It provided stiffening to the back edges and provided four wall-mounting locations, one at each corner. The new ones do not. The stiffener goes across the top and one-fourth of the way down each side. There are only two wall-mounting locations now, one at each top corner. Another consequence of this change is that the unreinforced cabinet walls warp and bow-in where unstiffened (a condition made worse by the shrink-wrap packaging), which, though not hindering drawer movement, is an aesthetic detractor. One could feasibly add stiffeners (or a panel) inside to mitigate this.
Finally, regarding label adhesion, I don't expect to have problems with these drawers. Sometimes a silicone-based mold release is used with parts like this during manufacture, so I may as a precaution use a wax & grease remover (acetone works great on polypropylene... but don't use on polystyrene) to wipe the plastic before adding labels.
****original review February 21, 2011****
Yes, although marketing materials and even the manufacturer's website shows CLEAR transparent drawers in the photos, and it even states there that the product features "See-through drawers for quick identification of contents", they are NOT TRANSPARENT. I asked a customer service rep (Stack-On Products Company, [...] Ph: 1-847-526-1611 Toll Free: 1-800-323-9601) and she said that they are translucent, like a plastic milk jug (which is usually made of polyethylene), and have been this way for quite a while. She did not apologize or explain the false representation of the product when I mentioned it, which I must assume will continue uncorrected. It seems that there would be a lot of complaints and returns, tho??!
I have 6 units (DS-60) from about 10 years back. They have clear polystyrene drawers, but some have become milky-white opaque where morning sunlight comes in through a window and shines on them. The others are still clear and doing fine. But I needed see-through drawers and was about to order two replacement cabinets to get the drawers. *Thank you, Amazon Reviewers* for calling this to my attention:-) One may, BTW, order REPLACEMENT DRAWERS (No, you can not get any 'old' clear ones), by calling them: $0.50/ea for small drawers like the DS-60 uses, and $1/ea for the larger size, plus priority shipping $4.05 for up to 10 drawers (as of 2/2011).
A note regarding the two plastic types: The discontinued polystyrene (clear) is more rigid, cracks more easily, can be easily repaired by gluing (is not resistant to many solvents), and labels will adhere easily and stay on over time, possibly even being difficult to remove. With polyethylene (and polypropylene), the opposite is true in every case: These plastics are naturally milky-white translucent, they are flexible, not easily cracked or glued (are quite resistant to most chemicals), and labels will need quite a strong and durable adhesive to stay on over time. Paper labels and labels meant for use on paper, for example, would probably not adhere very well, especially in a warm environment.