For heavy construction and demolition, I use a 3lb sledge hammer. In the past I have always purchased quality, name brand hammers with wooden handles. Every year I break at least one handle, and the cost of the replacement handles is almost as much as a new hammer, so I just buy a new hammer.
I just broke another wooden handle, and went to buy another sledge hammer. The place I went, no longer sells them with wooden handles. They are all fiberglass handles now. I bought one, it cost about $3 more than the last time I bought one with a wooden handle. But if the handle lasts longer, it will be well worth the extra $3.
But are they any better??? Will figerglass last longer? Somehow I cant see where glass strands and epoxy will be stronger, in fact it seems like it would be weaker. But I needed the hammer right away and did not want to waste hours going to other stores.
Personally, I think those heavier hammers should have steel handles, and I mean thick steel, not that cheap thin pipe they use on some cheap carpenter hammers, which comes with a rubber grip that keeps sliding off the handle.
(I'm seriously thinking of welding a piece of solid steel rod into one of the hammer head of one of the broken handled hammers I have. I know that wont break). Of course that will turn a 3lb hammer into a 4lb hammer.