Pros: low water use, looks good, comfortable
Cons: a bit large
In terms of installation, the Pegasus is the same as any other toilet. With the exception of some tools (wrench, screwdriver, etc.) the toilet came with everything we needed. We did end up buying a second wax ring just to be sure it didn't leak, and a longer water line because the nipple on the tank is toward the front, whereas on our previous toilet it was toward the back. The instructions were good, and installation was not too difficult.
The "flapperless" design is pretty cool. The toilet flapper is the rubber piece that essentially acts as a plug to the water drain inside the tank. This toilet instead simply has a 1.28 gallon container which fills up with water (see images). Once it reaches a certain level (the 1.28 gallon mark), the water shuts off automatically. When you push the handle to flush the toilet, it simply rotates the water container to dump out the water, and it then gets refilled. Very simple design, and it works great. Despite the low amount of water used, it flushes everything without a problem.
This particular toilet has the elongated bowl design. Personally I prefer the round bowl design, but they didn't have any ultra-low flow round bowl toilets at Home Depot. It's a very nice looking toilet though, and comes with 3 handles to choose from (white, silver, and brushed silver). It's also a little extra tall (they call it "comfort height").
Overall I'm very happy with the Pegasus toilet. It looks good, saves a ton of water, is cleverly designed, and works great. It's a relatively inexpensive toilet too. Many of the 1.6 gallon toilets were over $200.
A year later it's still working great. It's only clogged up once and almost always flushes everything down on the first try. Works just as well as any toilet I've ever had.