I have done a lot of renos in my home and replaced all three of my toilets with low flush models and they are not created equal.
The first two that I bough were not the cheapest but one of the cheapest model and they flush ok but really slow and one has a tendency to get blocked on occasion (only twice in 5 years but even that is too much).
The latest one that I purchased was the Cadet 3 by American Standard and let me tell you this think is one crazy toilet.
I got it at home depot and the sales guy was tooting this as the Cadillacs of toilets.
http://www.americanstandard-us.com/products/productDetail.aspx?area=bath&cat=3&col=&prodID=1806It has a enlarged flush valve that allows for a quick drainage and superior waist per second drainage. Apparently this is what you want in a toilet, the quick drainage causes a suction that will suck out any of your waist in seconds. There are several different versions of the same toilet the one I got has an Elongated boil and sits higher (I think 18") off the ground. It also comes with some silver something in the paint that is anti-microbial so that the toilet will stay cleaner for longer.
I've only had it for a few month now but it is my go to toilet for the big jobs. You know like post Christmas dinner, post easter dinner.
This sh1tter does really suck!! in a good way.