High Tank Water Closet - efficient?

Hi,
I'm going to install a second bathroom in the basement and would like to use a high efficiency toilet. I'm wondering about High Tank Water Closets, how do they perform with respect to water consumption? (Are they practical?) Are there better alternatives that I should consider?

In the US, any new toilet sold today must meet the 1.6gallon per flush maximum. Some use a little less. Some toilets work quite well, some are abysmal. Go to Terry's home page and read the ratings/reviews and read some here.

toilet

If you really mean a "high tank" toilet, meaning one with the tank near the ceiling they have much better flushing than a low tank because of the higher pressure generated by the added height.