We have engineered beech in a condo. It has been extremly dimensionally stable in a rather hostile environment. However, the underlayment must be stiff, and that means no OSB, etc. The engineered product is not as stiff longitudinally , so if the underlayment flexes, so does the engineered product.

osb isn't generally recommended for solids either.

We have acrylic-impregnated engineered hardwood in our kitchen. We chose it because we're on a slab and were told it was our best option. I smiled at willinak's "hostile environment" comment because it certainly fits my situation. It's been down over 2 years and has held up to large dogs running, 3 small children and riding toys and two doors that open to the garage and backyard. We are not a shoe-removing family. It's from Hartco.

I have solid wood, NOT pre-finished, in kitchen and engineered on slab in den. A friend has solid that was pre- finished in factory. We both agree that finished on site is the best. I'm not sure if you can do that with engineered flooring. If I had a choice I would go with solid finished in home. Just my opinion.

There is no way an on site finish can come even close to a prefinish. Many prefinish companies are applying 10 coats of finish, and now placing the aluminum oxide layer on top. There just isnt an on site finish in the world that will compare to the hardness. However...there are some reasons on occasion where pre-finish should come in to play. Only time a consumer can tell the difference is when the are looking at it out of the box. But hey, there is a reason why they make a 100 different flavors of ice cream.

Companies vary in how hard their coatings are and the advent of some scuff-resistant formula (like Anderson's), etc., in my view probably arose because of deficiencies in some of the prefinished flooring out there. And I believe placement of the aluminum oxide - on the top layer or under the gloss - affects the shine level.

Of the wood I scratch-tested, the best was an engineered jatoba from Lumber Liquidators that was pretty matte - betting it had aluminum oxide on the outside. Anderson's 'chocolate truffle' maple solid held up quite well as to the finish - still the wood itself is not so hard/

We ultimately bought a solid prefinished handscraped (BR-111 Armagnac Angelim) but I think there is still definitely room for old-school, old-world beautiful finish-on-site solid floors. (Not speaking of hardness per se.)

I'm going to disagree with echo here in practically only, as I am not a wood floor specialist, I do not make, sell, distribute, etc any flooring product. I am just a homeowner who initially installed prefinished, engineered veneer oak flooring. The veneer of wood was 1/8 inch thick. I will qualify this by saying that it was 1998 (and I am sure they are much better made now) when we installed and it was an expensive floor and costs us several thousand above our builder allowance for wood floor.
We had a newborn, a 20 month old, and a almost 4 yr old at that time. This floor was in the entry, a path separating living/dining leading from one end of house to another, kitchen, and 2 baths. Within months, the baths were ruined from water splashes (and we were ogre diligent)and within 2-3 years, the kitchen ruined by the dishwasher drips, and the finish destroyed by daily wear and tear. In 2006, we went with a finish on site hand scraped, stained and sealed red oak that is also a veneer but the veneer is much thicker than the factory prefinished stuff. As for the seal, 3 coats were applied and 4 years later, it is still beautiful. Those little kids are now teens (or nearly) with lots of friends coming and going, plus 4 cats and 2 dogs. Minor scratches are covered with a sharpie or furniture pen and those we miss, are not noticeable. My favorite thing, is the joints got filled with the sealer. Things have been spilled that have not penetrated through the joints. Just this past April 2010, a hot water heater went out and emptied its contents onto this floor. Water flooded the hall 20-30 minutes before discovery. The water traveled under walls into another room (tiled bath and carpeted closet) as well as the boys carpeted rooms. The carpet was ruined. The wood floor stayed intact with no buckling, warping or damage to the finish. And this was HOT water. Go figure.
Long story short, I am not against engineered veneer (ours was made by corning which is not longer available but similar through Shamrock wood flooring) but I do not like the pre-finished stuff at all. Finished onsite, imho, is the only way to go.