I have a medium to long-hair Maine Coon cat who was suffering from hairballs every week, he hates grooming plus grooming him is hard since he has an undercoat and sheds like crazy. Tried many different brushes, shampoos, but non worked as well as this.
This thing works great and he actually enjoys it, grooming sessions have now become a great bonding time for us!
It is a little expensive but it's worth it, there are a few other brands that do not cost as much and these work well too.
TIP: it took a few sessions to figure out how to use the tool, I found that the instructions that came with it were wrong, I guess it will depend on your pet and his temperament. The method that has worked best for us is to start slow with very little "pulling", and once your pet has settled in and is calm (this is very relaxing for them), angle the tool down more so that it starts to pull a little and continue like that from head to end of the tail. Also, don't expect to get all the hair in one try, or even in one day. Will take many little sessions of 5-10 minutes to get the best results.