We're looking to replace... a Sterling Windham ...
It's elongated, but only 15" high.
The regular Drake, and many other Toto toilets, comes in 14+5/8" high height and in 1.28 & 1.6 gpf and elongated and round. Most here would say that the Drake is a "Best Buy," or "good bang for the buck."
What is your plumbing like? What year was the house built? How thick a toilet seat do you have on there now? (bottom of the seat plastic pads to the top of the seat). 3/4" is about the norm. The thick oak seats are about 1.0" to about 1.5", with the cover, about 2.5".
14.5" - 15.0" is the standard height for regular height toilets. ADA is 17", iirc. (The spec calls for 17.0" - 19.0" toilet
seat height.) A little lower, about 16.0", without seat, is "Comfort Height".
I went with a regular height toilet in the hallway for children in case I ever decide to sell the house and an ADA in the MBR for when the parents get older. I have arthritic knees, so it really helps. Using the regular height toilet at work is not a problem, though; at home it's a different matter. By the end of the day my knees are creaking. So I had to install a 1" Toto seat on the regular height otherwise I'd have problems standing up. Minor, but still painful. The opposite is also true, for a 5'0" woman, like my mother, the ADA would be too tall and painful getting on and off the throne. ymmv.