First two season are bangarang. Third season starts off okay, but has problems like how the only way to show character change is by physical changes (Apollo is fat, Adama has a mustache, Tigh is Cyclops), then scuttles their unique premise for more wandering aimlessly in space action. Which is okay, but eventually it settles into a kind of slightly grazes deeper themes and focus more on unraveling the Lost-levels of mythology. And some of the most interesting plots (Baltar on a Basestar!) go nowhere, and some things are explained but not really clarified or answered. Then it kind of all comes to a more-or-less satisfying finally that holds things together for at least the first two-thirds.
So yeah, I sincerely enjoyed it. The second-season destabilized enough to make it lose "Best On Television" status, and the remaining seasons just kind of keep it above water. That first season though, man, what a doozy.