Engineered hardwood can be installed over concrete directly. If you have a concrete floor, I highly recommend an engineered hardwood for that application. An other advantage of the engineered hardwood is that it is usually pre-finished. After it is installed, it is done. Also what you see is what you get. You select from pre-finished samples. That being said, some pre-finished engineered hardwood products can not be sanded after they wear and some less expensive one do not have a very thick wear layer. For a full thickness hardwood you can stain it and create a custom color. Also it can be sanded. The acoustical pads under the floor can work if they are installed in strict accordance with the manufacturer's instructions. They do have a different sound and feel to them when you walk across the floor.

Did anyone mention levelng your existing floors? This is normally an upcharge and is required if your floor is 1/8" out over 10 feet.

One note. Not all bamboo is the same hardness. It depends on how where the bamboo shoot it is harvested from. Also Mao Bamboo is a harder species then others so be careful with board statements like bamboo is hard because that is not always true.

Universal . . . since it looks like you're in the business, what is your take on solid wood vs. engineered? Floors would go over subfloor on 2 x 10 joists.

In most cases you will have many more choices with engineered flooring.
Here is a video page link that has a video about the differences between solid and engineered !

http://www.universalwood.com/videos.html

We replaced our 15 year old ceramic tile kitchen floor in 2005 with 3/4" oak hardwood (Bruce) and would make the same decision again. Two houses, two kids, two dogs -- and our preference has always been wood floors in the kitchen. In both houses we chose wood over ceramic tile, and did not have the option of engineered wood because we were extending existing hardwood. In our current home, we have had some "cupping" in an area that does not get water so I am assuming there is higher humidity below this place in the floor that comes from ??? Underneath it is an air duct that services a bathroom. Apart from this unexplained issue of wear and tear -- be sure that your stain and other finishing extends well behind the cabinet -- I have two places where there is no stain where there should be -- one is a corner where the cabinet comes forward an inch, and the other place is beneath my range. Like many ranges, mine is on legs and does not extend to the floor. It would be easier to clean his area under the range if it were finished like the rest of the floor!

For the upstairs, in replacing carpeting, we installed hardwood over plywood. Under these circumstances the wood can be less thick as the hardwood is not the floor for structural purpose-- the plywood serves that function. This may have been "engineered" wood -- but was really just pre-finished. I would not use prefinished wood in a kitchen because the cracks between the wood planks tend to be larger. In a floor finished in place, the boards fit more closely together, with or without the increases or decreases in humidity -- characteristic of kitchens.

I have even considered a wood floor in the bathroom, but would only use hardwood, not engineered wood because of the high moisture and increased potential for flooding.