I use it and I must say it's really brilliant - economical, clumps really well and you can flush it down the toilet. The only con is the tracking, but if you're willing to hoover more often, that shouldn't be a problem. It's also a bit cheaper than World's Best (which is very good, too).
I top up roughly once a week and, just like Ambercat, retain the good litter when cleaning the tray.

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"No-one can ever slow me down, I'll stay unbound"
(A7X)