I loved it. And i'm not afraid to admit that ending made me a tad emotional. That was a fantastic way to close the series out with a degree of resolution while keeping a thread open for continuation.
The closing shot with Eli looking out to the Universe and just smiling was brilliant. That's me. That's how I see myself and that's exactly what i'd do in his shoes. The odds are against you, the chances of surviving are slim, but at the end of it all...your across the universe. You've done something no one else has. That was a thread SGU only vaguely touched upon throughout its run, but I'm over the moon it decided to close on that. As dark as space is, it's full of wonder. And that's exactly what I want out of my Science Fiction.
As per the story, if, by some miracle we got a continuation 3 years from now, I now how the writers are gonna keep Eli alive. He's going to go into the neural interface chair and download his consciousness into the computer so he can get it on with virtual Gynn, and also so he can carry on trying to figure out how to keep everyone else alive without using vital resources like air, food and water. The neural interface chair also has some degree of cryogenics involved (thanks to scientist guy from s1 who I can't remember) so I could buy his body being preserved.
But that aside, I'm going to say again how great a finale this was. It beat the hell out of LOST for me, and I'm going to say its near enough the same level as BSG was for me.