"There are also cheaper compromises that only replace the toilet lid instead of the entire toilet and without requiring a hot water line."

Both the models I recommended are of this type (they are just a seat, and they don't require a hot water line).

I considered the model you recommended. The main reason I went for the higher-priced models is that they are higher-power, and can heat the incoming water in real-time. The more inexpensive Toto models are lower power, but compensate by having a built-in tank to store water. I guessed (but did not verify) that, on occasion, the tank could run out of hot water before I was done.

Does the tank on the B100 always have enough hot water for you?