Honestly, Siren's experience comes down to whether or not it's actually worth playing. Is it? Hell yes, of course. But the episodic approach (and especially those files sizes, something the PSN is not very good at delivering) is trying at best. The question, then, becomes, "is the game worth it per-chapter?" Noope, not really. It is, however, quite worth the total experience.
That things actually get better the longer you indulge in the chapters is something that Lost or Heroes or Battlestar Galactica fans will understand. No matter how addicted to the episodic ideal they may be (and make no mistake, it won't be a season's-worth of effort to finish Siren), though, it's still a stretch to ask everyone to ride out the game to the (lovably crazy) end.