I had previously purchased Worlds Best Cat Litter Extra Strength Formula 2x 7.5 kg
which is very expensive, but clumps well and does keep down odours.
This product is much cheaper (about a third of the price) and maybe ok if you have a litter box with a lid and a filter, but using open trays I found this did not keep the urine smell at bay. I kept getting whiffs of cat wee and spent a fair bit of time on my hands and knees trying to find the source (one of our kittens occasionally has the odd lapse) only to realise it was coming from the litter tray. Also as the pellets crumble when wet it is difficult to clean out the smelly bits!
One of the reasons for trying this is that I found World's Best tracked dreadfully and this litter didn't track at all, so that's a plus point. And when it is clean the litter has a nice 'woody' scent.
Wont be buying this again though, and am now trying a different clumping litter - Extreme Classic Unscented Cat Litter which is currently £24.90 at Zooplus for 30kg. It certainly clumps well and so far no pongy urine smell. Although, we are back to litter tracking again (sigh). It appears that all litters that clump will also track, so it is horses for courses.