The problem here is not all toilets are manufactured equally and not all are fully tested before sent out into the real world.

For example NYC had a toilet change out where the city had a win, win situation by encouraging folks to install a 1.6 WC in lieu of the more wasteful 3.5 GPF.

The reason this was a win, win for everyone who did their homework was for the following reasons.

1- The water saved from going down the sewer allowed NYC to keep the existing water tunnels working thus saving billions of dollars to install new aqua ducts.

2- People saved money on their water and sewer bills by conserving the water.

3- Licensed plumbers who did install these toilets were given rebates up to $240 per toilet in many cases the home owner only had to pay the tax ($19.80)

Before I installed any toilets in my accounts building I went to several trade shows and saw these devices in action.

Some were so noisy they could have awoken the dead besides being out right dangerous with excessive pressures generated in a piece of China that could literally explode sending shrapnel all over the place.

I opted to test a GRAVITY flow WC which cost $59.00.

I installed this toilet in my own office and tested it in actual real world conditions. I even had clients come to my office and try to stuff it up with 30 sheets of paper and what ever NORMALLY would go down these devices.

After 5 months I decided to sell only one brand of toilet that works perfectly.

I did try several toilets but they always seemed to need another flush to help carry away debris and thus wasting more water then the original 3.5

The 1.6 does work with no call backs I should know as I literally installed several hundred of them and one of my supply houses only sold this brand and over 300,000 sold NOT ONE CALL BACK or defect.

Unfortunately the expensive toilets, especially the pressure (NOISY) assisted ones did not do as well and I have 2, taken out of an embassy, that are less then a month old and sitting in my shop so the world can see what garbage is made of.

Conserving water is the right thing to do BUT not at the cost of possible disease and discomfort of the building owners.
There are still a lot of companies pushing inferior 1.6 toilets that make it bad for the good companies that have great working models.

In my opinion NOTHING BEATS Gravity flow as there is NOTHING to go wrong with nature doing what she does best; that being allowing water to flow down hill.

Now the horror stories about causing lots of stoppages just didn't materialize with the less water, what did suffer was the scouring action on the larger diameter soil lines But if these older lines are properly water jetted then the new lower flow toilets will scour just the actual area used and all the old build up of debris can be scoured away.

The old owner of my office had another brand of water saving toilet installed really expensive type BUT his water bill was over $500.