I know I am responding long after this was posted, but happened to come across it. I have an Expanse, and no, it is not smaller than a conventional tub, it is larger. It is both deeper and wider. The arched front apron makes it wider than most conventional alcove tubs, but no longer.

It takes a lot of hot water to fill it and is a bit difficult to clean due to the width and tall front apron. However it is great for showering. It gives you as much area as a conventional shower stall.

thanks, had hoped it was a similar size, but after reading the large width dimension. I could not even walk up to the sink.

It comes in two sizes. We have the smaller one. Which were you looking at?

the smaller one, but at a bow of 36" wide, and a vanity that is only 4" away from the tub, 18" deep vanity.

Do you want/need additional info about how it would fit? I am not home currently, with the holidays, but will be later this week. If you want specifics about how that bow would relate to the vanity, I could measure for you. Let me know. (email is "open" on GW)