Pros: Low water usage
I read the reviews here, and thought the worst problem would be the water splashing out the back, which sounded fixable, so I bought one. At first I too had water on the floor after each flush, but it wasn't coming out the back (which I'd duct taped anyway, just in case). Turned out it was leaking from the gasket between the tank & bowl, and after tightening the bolts more than I thought I should, the problem was solved.
The worst design problem I think is with the seat. First, the bolts holding the seat down are much smaller than the holes in the toilet, and so there is too much play with the seat. A little squirming results in the whole seat sliding over the edge of the bowl. I think I've solved that by putting a ring of tacky material under the seat around the bolt. There should be a bushing, but this seems to work too. The next problem is probably due to the plastic nature of the seat, which allows too much play between the seat and hinge, but it is exacerbated by the slippery landing strips (I can't think of the real name) under the seat. I fixed this problem by putting a layer of silicon calk on each strip. Finally, when sitting on the cover, any sideways movement causes the cover to slide off of the seat to one side or the other. I'm still working on this one. All in all, kind of shabby for a seat supposedly designed for the toilet. The slow close thing works okay, but it is probably not like an expensive seat, and may not continue to work as well as when new. Oh, and the seat would be a lot easier to put on before the tank is bolted. It's not really a problem, just an annoyance.
Finally, so far it has not shown any signs of clogging, but it also hasn't left a completely clean flush. Testing and adjustments continue. It works well enough that I calked around the base and sent in the city rebate form, so there you go. One thumb up.