Depends on what you're into. Personally, I would find a Zac subplot more interesting than Patricia, who to me just feels like a character who we've seen a million times in other VNs like this, but again, it's just a matter of personal taste. I'm an enjoyer of "younger guy of an unspecified age seduces/gets seduced by an attractive older woman, usually a teacher or friend's/girlfriend's mom" scenario. I'm not into lesbian or incest stuff, so I just have to sort of wait those subplots out to get to the good stuff.
I would consider Zac a non-entity if it weren't for that exchange at the tanning salon.