It seems to me that it's not really SF at all, the way "Star Wars" is not really SF - it's a story that happens to take place in space. SF tends to be more science-technology oriented, relying on exotic concepts. In both "Galactica" and "Star Wars", these are peripheral to the story - we accept that there is such a thing as FTL drive and it is never explained (no warp drive and attendant appendages as in "Star Trek").
However, it is indeed a great series (currently showing on one of the German channels here), good stories, good, meaty, flawed characters trying to cope with the unthinkable. I only hope that they can keep up the standard - and that they don't have to compromise because of US ratings. I hear that it does pretty well in the ratings, so I'm hopeful (remember that Roddenberry's original "Star Trek" was originally rejected as being "too cerebral").