I just worked by way through TNG and DS9. TNG took a while to get it's legs...in today's environment it wouldn't have lasted past season 2. But then it became great television for the rest of the run.
DS9 started pretty solid, and became one of the best written pieces of sci-fi TV quickly for a long time.
DS9? Yeah, it starts pretty soap opera-ish. That never really goes away (they're kind of stuck on the station for the most part), but the stakes get higher and higher and the various players and factions involved become pretty interesting. Not quite Game of Thrones, but way out of character for a Trek show.
