We have the Kohler & it is well-done from that respect. Do note that the nonskid stuff they are putting on pretty much all the tub bottoms can be hard to clean--Bar Keepers Friend works the best for us. Hope this helps!

I am actually putting a bathroom in the basement first, before I remodel the two second-floor baths which both need to be remodeled and will both need to be done simultaneously since they share a wall and that wall is moving. We lived through a kitchen remodel that left us without one for 4-1/2 years :(. By having a full bath elsewhere I hope to not have to make any finishes decisions based on timing...we'll see.

CLR is a mix of acids. Usually the calcium will dissolve in acid, but sometimes soap will not. If the tub is in daily use, you could spray it with Clean Shower after every use. Eventually (month or so) the alcohol in Clean Shower will soften both the calcium from the water and the soap scum. Both calcium and soap dissolve in alcohol. Then you can use a plastic scrubber (I used a Choreboy type scrubber). If the tub is not in daily use, you could spray it at least daily with the same stuff for a month or two - then scrub with the Choreboy. Daily use of Clean Shower has kept my shower clean for years with pretty hard water.

flyleft: same advice applies -- as long as the framing below was done to code and has not been compromised by rot or brain-dead plumbers, you should be fine. A simple test is to put a bucket of water on the floor and jump up and down around it. If you get significant movement in the water, it may need to be stiffened. Remember that just two or three good-sized people (say 200 lb. apiece) are going to put far more load per square inch than any tub.