My experience is that some cats really get into catnip, others enjoy it sometimes, and others don't pay any particular attention to it, one way or another.
My Zyelena used to really, really get into her catnip. Any catnip toys immediately became hers
, and she'd hide them from the other cats in the most creative ways then pull them out when she wanted them(she's been gone for 3 years now, we still find her toys occasionally.) She would roll the toys by pressing down on them with both front paws and rolling them back and forth like a rolling pin, then stick her face into them and inhale deeply for a while, then walk around the house, high as a kite, saying the cat equivalent of "Oh wow!" "Oh wow!"
Menelaus was who she was usually hiding the toys from. He loves playing with catnip toys, it gets him really wild. There are a couple of times a day when he gets especially playful, and he likes the catnip toys the best, and he gets especially ferocious with a catnip toy versus one without catnip.
Yuri and Phillip only played with catnip toys because the other cats thought they were special. They liked to get the toys away from the others as a dominance game, but the catnip had no special effect on either of them. Yuri obviously noticed the smell of it, but his favorite toys were a puffball on a string and a ball in a wheel. Phillip would sniff as strongly at a non-catnip toy as a catnip one, he wanted to know whose smell was on what all the time.
So yeah, I think there's a lot of variability between cats on how they respond to catnip.