I noticed with some of the extremely long crabide tipped teeth, like sandvik, W7's, W8's and some of the other kennametal teeth, that they flat spot before you get the full wear on them.
I also noticed that having a puller groove seems to make them flat spot because material builds up in one side of the groove and causes them to stop rotating. We have stopped using teeth with puller grooves altogether. We get better wear and having the groove in them actually costs more.
I currently have a set of Kennametal RZ07's or 302's, I guess they call em now, that have over 80,000 Sy's @ 2" on them and still going strong. I have had great luck with kennametals RZ06's and RZ07's. I'm interested to know how the eco teeth do, please let us know.