Right after I ordered one of these, I found that CUWCC had the Eco Drake series tested. At first I was bit concerned after seeing the test results. There is a bit of a spread in the MaP testing results. I ordered the standard height elongated which tested at 600grams while the ADA height tested at 900grams. After a bit of thinking, I figured that I am probably OK with this. My biggest concerns are with clogging and not so much worried about whether or not an extra flush will be needed. My guess as to the difference is that the added height of the ADA model provides a bit more siphon action inside the trapway.
When my order arrives I will be able to get rid of the last of my 1994 era builder grade Briggs 1.5l units. These first gen low flushers were really bad. Puny water spot and way to easy to clog.
Link to the MaP test results, see the section on the 1.28l flush models: