^Agreed, at least about the first five being the best. Six wasn't the same without you-know-who, Seven had a strong storyline and cool moments but somehow wasn't that memorable, and Eight was intended to be and probably should have been the final season. The season Eight finale was AWESOME and would have made a great ending to the show. Nine and Ten really weren't the same show and all in all couldn't live up to the earlier seasons.
Having said that, there are awesome episodes in every season, and I somewhat disagree that they abandoned a lot of plotlines, there were some things that could have had more detail but I (personally, just my humble opinion) was usually satisfied with the conclusion to the story arcs.
SGU is weaker than both the preceding series, definitely, but I do think it's watchable. It's just...hazy, incoherent, and can't decide if it wants to be dark and gritty or not (interspersing despair with jokes about socks, for example), and above all takes itself too seriously. Then again, most shows do. I'm still gonna watch it, but it's definitely not the same.