Solver,
C3C has some neat new features (as discussed previously), probably the most noticeable is the resource scarcity. But it remains Civ 3 at its core.
Of course, I bought it. Heck, I didn't even read the forum until AFTER I'd played a few games--at which point I hit the forum to figure-out what was going on w/ this game.

If you like Civ3, you'll like C3C. For me it was worth the price (but then again, I received it as a gift, but I would have bought it anyway.)