This is one of my favorite sci-fi shows, but I certainly recognize its flaws.
The Good:
* the concept
---> I liked the historical context of the 12 tribes of Kobol, the Pearl Harbor-like attack, the "ragtag fugitive fleet" seeking Earth. This really framed the series well.
---> The look of the Ceylon base ships and the bat-wing Ceylon fighters was terrific. I also liked the look of the battlestars and Colonial vipers. The command center of the battlestar seemed believable.
* the casting:
---> Lorne Greene as Adama brings a commanding screen presence
---> Richard Hatch as Apollo is well-cast and believable as a leader/captain of a fighter wing
---> Dirk Benedict as Starbuck the amiable sarcastic sidekick
---> John Colicos as Baltar oozed evil with perfection
---> other minor cast members like Herbert Jefferson Jr as Boomer and Terry Carter as Colonel Tigh were very well cast too
---> I thought the three most visible female characters were all good, though not standout. Maren Jensen, Laurette Spang, and Anne Lockhart just also happened to be beautiful too.
---> visiting cast members like:
-------> Lloyd Bridges as Commander Cain was truly memorable
-------> Patrick McNee as Count Iblis was also highly memorable
-------> Ray Milland and Fred Astaire were good guest stars too
* the costumes
---> I liked the Colonial Warrior uniforms - they still have a style to them today. I liked the Warrior helmets with their Egyptian-like motif.
---> The Ceylon warriors with their shiny armor, had a great look to them too. The red strobe they used for vision was a great menacing concept.
* some episodes with great plot lines
---> the return of Commander Cain and the Pegasus stands out
---> I thought the visit to the "home" planet of Kobol, with its Egyptian motifs, was terrific. This is part of the pilot's introductory three episodes.
---> I also liked the encounter with the Ship of Lights and Count Iblis - this was especially well done.
* the music - I still like the theme song to Battlestar Galactica
* the behavior of the Ceylons was entertaining. "By your command" spoken in a tinny voice was a favorite.
The Bad:
* some cheesy special effects (by today's standards)
---> ...and reuse of the same special effects
---> why was Count Iblis' crash site off-color in one moment, and clear blue the next?
* quite a lot of cheesy cringe-inducing dialogue
* the little kid Boxie and his robot dog
* some of the episodes had really horrible plot lines, especially later in the series
---> the Lost Warrior where the kids attack the Ceylon outpost
---> why did Baltar return to the human fleet again?
The Ugly:
* the original show was cancelled after one season
* Galactica 1980, the follow-on show in which the battlestar finds earth, was pretty horrible
All in all, I am willing to forgive Battlestar Galactica's flaws and remember with fondness its strengths.
Rick