Works To A Point
I decided to buy this cleaner because I have tried in vain a ton of other cleaning products to help with the smell of cat urine.  We have one carpeted room in our house where my 12 year old cat likes to pee sometimes if we do not clean his litter box right away.  He is a picky little butt head.  There always seems to be lingering smell and of course the carpet is light blue so it is super hard to get the stain out.  When using this I was obviously a bit skeptical.  A downside is there is not ingredient list on the bottle which would be nice to know what kind of chemical I am spraying in my house.  There is not really a strong smell to the spray which is nice because with other cleaners if it doesn't smell like cat pee, then it smells like I'm bathing in Lysol.  First the stain color itself, it did seem to fade an older stain that was on my carpet using a good soaking of this.  Also, I made sure to rub firmly to make sure it got down to the bottom of the carpet.  The smell has been reduced on an old and new stain, and in my experience seems to do better at this than other products.  I still however notice a faint smell.  Perhaps I need to use more of this.  Also, I'm not sure it could remove the smell forever unless you really soak it into the carpet padding.  For the price you pay, it does seem to me like this works a bit better than other cleaners, however, I'm not sure it will really eliminate the odor completely without using a whole bottle, tearing up my carpet, or getting rid of my cat.  I'm not planning to do  any of those three.
Rating: 4 stars