I owned a Big Bertha C4 driver over 10 years ago. It has so many bad reviews because it has a carbon composite head instead of titanium (no feel, bad sound, etc.). Back then I thought that it was a solid driver that performed about as well as others I've tried. Well, recently I saw the low price for a C4 driver at Global Golf in very good condition, so I went ahead and bought it. I have to say that even though this driver came out in 2002, I still hit it pretty much as far and as accurate as much more recent (and much more expensive) drivers. I have come to finally realize that "it's the surgeon, not the scalpel". So I'm going to put my Big Bertha C4 driver in the bag, and I expect that my drives will be at least as good as with any other driver.
I have used the Callaway C-4 I purchased from Global Golf off and on for 2 years now. It has a unique sound but always seems to be in play. A great option for the price!