Best RFID tag in the world ?

EcoTag looks like the best passive tag in the world, 11m distance.
But why no one use it yet? Any problem?

http://trolleyscan.com/isosys.html

sure, a lot of problems!
seems 11 m is distance achived Trolleys at demo, we had even much better results - up to 35 m (! - passive tag , 1 w interrogator).
But this is not mean that this tag will be so perfect at real world.
seems trolleyscan have no really nice results because they have no real movement in business from~2000 year.
for real results look at phillips and rockwell,
usually 7-8 meters is the limit for operation reliable enough. (900 MHz@1w)