I have both the CCK and the wokshop cleaver. Note that just because they're both "carbon steel" doesn't mean that the steel necessarily the the same! Carbon steel can vary in alloying elements, heat treatment, purity, hardness etc. That being said, I haven't sharpened the wokshop cleaver or used it a whole bunch, since I bought it to leave at my parents' place for my use when I visit. So, I can't say about the steel.
The CCK is a much better finished knife, though. The wokshop cleaver has a lot more rough edges. The bent part of the tang, for example, where it exits the handle on the wokshop cleaver, sticks out farther and is a lot more-square. The wood on the handle also seems different between the two knives. The CCK is a hunk of wood; it seems to be happy with a little bit of sanding and applications of mineral oil. The wokshop cleaver handle, on the other hand, seems to be made out of some sort of composite or laminate. Whatever it is, it just doesn't seem to be the same stuff or as nice.
Size and shape and weight are very close between the two cleavers. I measure the CCK at 214 x 90mm and 268 grams; wokshop 210 x 89mm and 266 grams.
To sum up, I LOVE the CCK cleaver. It is one of my favorite knives, maybe my favorite one. I use it a lot. At $40, it is a great deal. Easy to sharpen, cuts great, nice profile, pretty reactive steel, but so what? The wokshop cleaver is well worth the $18 ($10 plus $8 shipping), but I'd say the CCK is worth the extra $22 if $40 doesn't sound like too much to spend.