I never finished SGU back when I first got access to it. I've finished both SG-1 and Atlantis countless times. I remember watching most of the SGU pilot episode and quitting. I thought it was being too overly edgy and grimdark, trying to follow in the footsteps of the Battlestar Galactica reboot. I couldn't stand the idea of a Stargate show that was just characters being awful to each other.
Recently I tried giving it another shot and made it through the pilot episode. The characters are still abrasive to each other, but much less than I remembered, and they seem to for the most part mellow out a bit with each other as the episodes progress. I just finished the forth episode and I do want to continue. I am hoping they start actually doing something more than "the ship is falling apart we need to do something to fix it" plots, but I suppose the show really is trying to plant the setting.
Unfortunately it takes a while to settle in to meaningful stories. The latter half of season 2 is, in my opinion, on par with the rest of the franchise, but by that time they had already been cancelled.
It's the only one of the three shows that I don't rewatch. It doesn't lend itself to rewatching due to its drawn out pacing. Barely anything happens in each episode.