Right now, the ony thing that irks me is the unsteady camera work. That gets to be a bit much.
In general, the show displays many of the "we are not Star Trek" themes that have crept into media-SF of late: darker filming, slug-thrower weaponry, more limited technology, single-season story arcs, less reliance on technology to solve problems, more focus on the human aspects problem solving, and ambivilent endings.
Some of these changes are fashionable. (Darker is in. More "mature" themes are in.) Some are budget oriented. (Bullets are cheaper than animating in energy weapons. Small instrument combos are cheaper and more flexible than large orchestras.) Some are technology oriented. (Today's cameras are much better at filming in low light.) Some things follow from arc-oriented storytelling. (You don't need to wrap up your story every episode. Last week's story supports this week's story.)
Both B5 and DS9 are shows that started us in this direction. Voyager reversed that trend, sending the Trek series into humdrum land. Hercules and Xena occupied the "campy" spot on the dial, so strongly that SF could not return to those campy roots. (Let's face it, original Trek was campy.) Farscape and Stargate both had these elements.
On thinking about it, I am really very surprised with how much Buffy has in common with BSG. Buffy is the series that demonstrated how well a one-season story arc worked, and how that is done. It abandoned the orchestral soundtrack, has no rayguns, focused on the characters and their imperfections, worked in single-seaon arcs, often had ambivalent events, and generally kept touch with the problems of being a person. I think the entire industry learned a good lesson from that.
The other big influence is BSG was "Hill Street Blues" and the adult dramas that spun out from that in the late 90's and eary 00's. That's the style of drama present in BSG. I really don't know much about that genre, but it is nice to see that it works well in this setting.