I have an 8" chef's knife from Henckels Zwilling (it has an integral bolster and handle scales that are riveted on — I'm not sure what the series is), as well as a bread knife, paring knife and utility knife of the same series (the latter two I never use). The chef's knife is what I use for nearly everything and I like it quite a bit. It has surprisingly good geometry — I measured it at 0.005" behind the edge — and the balance is good. There are two things I don't like about it, though: 1st, there is an odd design flaw where the edge is pretty flat leading up to the bolster, which runs all the way down to the edge. This means that after just a few sharpenings, the edge will be higher than the bolster, and most of the flat area leading up to the bolster will be useless — this is the area that is used most often. To fix this, I ground down part of the bolster on my belt grinder. I don't recommend doing this without knifemaking experience. F. Dick knives also have this issue (and some other issues that I could list) but I believe Wusthof knives don't.
The other issue is that the steel is relatively soft; I believe it's only RC56. This is soft enough that it won't break if you drop it, but I'm a little disappointed in the edge-holding ability.
My girlfriend also has a set of Henckels from the Four Star series (not the four star 2). She has a couple of paring knives, a european chef's knife and a santoku. Her chef's knife is several years newer than mine (I got mine in 2003; hers are only about three years old). I don't like her chef's knife nearly as much as mine. It is thinner at the spine, about the same thickness at the edge, but it just doesn't cut as well. I believe the bevels are convex rather than flat on my knife. The steel doesn't seem to take an edge as well or hold it as well. The santoku is even worse: it's 0.01" thick behind the edge, and it will not take or hold an edge for anything. It also has a flimsy feel to it.
A few years ago I bought a friend of mine a Henckels Forged Synergy santoku. For the money I paid (about $40 at target) it's not a bad knife. It doesn't take or hold an edge particularly well, but the geometry is pretty good. I actually like it better than the four star santoku.
So Henckels are a mixed bag in my experience. You can do much better but you can also do much worse. Since yours was free, you have nothing to lose by using it. The only real issue is whether or not it works for you.
- Chris