Empirical question

I am aware of two people who have seen Before Sunset, but not Before Sunrise. They didn't like Before Sunset. On the other hand, everyone I know who has seen both, including me, thinks both are great. So my question is whether or not Sunset establishes Jesse and Celine as interesting characters in and of itself. Based on my extraordinarily limited results, the answer is no. This seems like a reasonable hypothetical to me, but I can't really tell what I would think about the characters if I hadn't seen there first encounter. If anyone wants to compile a sequel depdency ratio, I'd be interested in contributing. Here's an obvious place to start. The valuation I place on Aliens has, I think, no relation to the valuation I put on Alien. I like both, but I like both independently. This isn't true of Sunrise/Sunset.