Product review (5 stars): all 3 cats love them, and they seem to work
All three of my cats love these treats, and they go all-but-nuts when I open a new bag.

Besides making my cats happy, the treats also do seem effective at reducing hairballs, especially for the shorthair who throws up most frequently otherwise. And they entirely eliminate hairballs from the other two cats (another shorthair and a longhair).

Mind the directions-- these dense treats seem to work by helping the cat swallow any stuck fur, so you should feed your cat several treats at once to provide enough volume to force down any fur that's in the way (I do 3-4 treats per kitty per serving).  Besides the major benefit of reducing the amount of hairball cleanup (and feline discomfort), these are also one of the few varieties of treats that all three of my felines consistently enjoy.

This treat is hard to find at local stores (and expensive at the ones that carry it), it's a bit cheaper here especially with Subscribe + Save.  The batch I got in Jan2014 had a sell-by of Sep2014, which is acceptable for a pack of ten.

Highly recommended.