Let's talk hardwood flooring. Who's got them or has had them? Pros? Cons?

[William]

Thanks for chiming in. This floor would be installed above grade and on a wood subfloor. The basement will be mostly carpet with a few areas going to be finished concrete or tile.

Due to our house being green-built the builder won't honor warranties if a humidifier is added as they even have fans on humidistats to remove humidity before mold becomes an issue. From this aspect our home has better humidity control than most and, correct me if I'm wrong, but it's the changes in humidity that can cause issues with hardwood flooring, right?

Yes, that is the major concern. If the water content of the wood drops below 7% you can have major issues with the wood cracking and splitting. I have heard of this happening in Colorado, but have never seen it myself. Relative humidity would have to get extremely low for that to happen.