if you hunt modern sites say post 1960's with a lot of junk, you will mostlikely be dissapointed in the results of the CZ3d, especially if your hunting along side someone with a CZ5, which was replaced by the CZ3d.
Now older sites, the CZ3d is a good machine as long as theres very little trash, because you will dig a lot of trash with the 3d. Also as far as nickels go, I still have yet to find a nickel with the 3d that hit in high tone and registered nickel on the meter. Nickels always hit round pulltab on my 3d with mid-tone, I then flip to salt to check every pulltab before digging it to see if it says nickel. Also if you want to notch out zinc, the only way to do it is to flip to salt mode and turn discrimination all the way up to 6. But it enhanced mode, no way to notch out zinc.
Now, on the C$, this machine as Mr. Bill says is more universal. Its a great coin, relic & beach machine. I always tell people when asked about the learning curve is that it took me a good 40 hours to really become comfortable with C$. But some have picked up on it right away (lucky them) because I think most don't and that is why there are so many listed for sale or trade. The C$ is a commitment machine like the Explorer & DFX, yes, I place the C$ up there with the top machines because Its every bit as good and in some cases even better then the other two top detectors.
Now, ou also have the ID Excel, which is almost half the money of the Coinstrike but packs a lot of the C$ features. It too is a good relic, coin & beach machine as well from what i hear and for the bucks its probably the best deal going on a new detector.
Just a few ramblings from someone who has nothing better to do then throw in his 1 1/2 cents.
Good luck,
Mike