SG-1 has its moments, but for me it never had a chance of overcoming the handicap of being based on such a piss poor movie as it was. I regard it as fluffy filler. But like I said, it does have its moments, and it has some strong episodes.
I think one of the problems that the show had on a regular basis was that none of what happens appears to have any relevance outside its own little fantasy universe. While there doesn't always have to be a universal literary theme in science fiction, it helps if there is one more often than very rarely.
Once the Ori came on the scene it was a dead show airing.
As for how I rank it, overall it's better than DS9, VOY, ENT, SGA, SGU, First Wave, and Falling Skies, just to name a few, but not as good as TOS, TNG, nuBSG, X-Files, Walking Dead, The Clone Wars, or Twilight Zone (TOS).