Nearly as important as the way a bath tub looks is the fact that it needs to be filled efficiently and conveniently. There are two options that work when the tub is large enough (70 gallons or more); each delivers a vigorous flow of water quickly.
Should you choose an exposed or concealed tub filler? They are confusing terms for an often neglected topic. The bath fitting can be mounted on the deck of the tub, called “concealed,” or it can be mounted on metal legs, called “exposed.” In either instance, there are many design options and the choice should be compatible with the lavatory fittings you have selected to reflect the design style of the space.
If a tub is not filled quickly enough, the water will inevitably be cold by the time it you get in. That is why the volume of water is especially important. Achieving the necessary gallons per minute (GPM) is dependent on the plumbing behind the wall; ideally 3/4-inch piping. Fifteen gallons per minute is the recommended flow rate. That means a tub measuring 6×3 feet will fill in approximately four minutes if you install the proper filler.
This is an issue you must discuss with your contractor and sales consultant, but be sure to double check the information you have been given. It is nearly impossible to make corrections once the walls are closed.
However, after making sure the technical piece is right, you now need to make decisions about the visual and convenience standards. The questions are: Do you like a fitting that is mounted on the tub deck, either on the front or back or possibly on the wall. Or is your preference for seeing the fitting mounted on legs with the hand shower hose exposed? I would say that the concealed installation is more formal, while the exposed can feel more industrial or casual.
There are a number of installation photos in this post to help you make the decision. Neither is right or wrong. It is a personal preference.