Mostly, the opinions of most of the users of this form is that AS toilets are not very good. Why don't you look at the Toto line. They may cost a tad more than AS, but are far better quality and perform better. Warranty on toilets is somewhat of a joke. If the toilet has a problem, it is there from day one. The only wear parts are the fill valve and flapper and all of them eventually have to be replaced. Not expensive nor hard to do. The Toto 1.28 gallon per flush (same as your 4.8 I believe) are working very well. It appears that the 1.28 is going to be the new standard very soon. But, if you go to the very low volume of water, you'd better be sure the toilet is a good flusher. If you have to flush twice, then you're right back at or near the old 3 gallon per flush toilets. I am not a fan of dual flush, but that's just my feeling.