I've laid solid, engineered and laminate over the years .
Solid is straight forward but I have floored three houses over the last year using engineered oak flooring in both oiled and laquered finish.
In Ireland ,at least down here , suppliers will only give a guarantee on engineered flooring due to the problems caused by the damp atmosphere .
I've got solid Oak throughout my house which is glued down but the engineered timber was laid as floating floors , both straight onto concrete.
Neither have given any problems at all but do follow the well documented rules of laying timber floors.
In saying that I did once encounter a problem once on an Ash floor where the timber had been supplied by the client. It was straight from the timber yard and in long circa 4 M lengths . The lengths were actually slightly " Banana " shaped which caused fitting problems which meant the timbers had to be clamped to get a parallel fit so I'd suggest you stick to lengths of less than 2 to 2.5 M to avoid this .
The large house I laid the oiled engineered floor looks the best actually and if you are selective in your choice you'll get at least two sandings from a good engineered floorboard.
I'd avoid laminate if you are serious about timber flooring although sometimes " Needs must " .