I've been buying this product for my cats for over 7 years, occasionally trying something new, but always sticking to the ground chicken. It's pure protein, and cats are carnivores - they don't need all that breading and congealed whatever is in kibble.
They love it, and consistently get tons of positive feedback from their vet. At 10 years old, my eldest hasn't had any medical issues whatsoever, and still plays, runs, and chases like his 8-month-old sister. He doesn't look 10 seems to be the general consensus.
The fermented fish went over really well, and it's likely to become a regular part of our monthly order.