Be honest, most sci-fi shows these days are pretty shit as well. There's nothing about them that is so good as to attract people who do not usually watch sci-fi.
I like sci-fi, and SGU is decent, but it is saddled by aimless and sloppy writing (please let me know if this has changed at all in season 2), mindless action, and pointless sez, just like most other drama shows are. Its mediocrity is only buffeted by the fact that it is one of the few (perhaps only) remaining shows in a genre we all enjoy. But for the majority of people who don't give a lick about sci-fi, there is just no reason for them to try to get into yet another average TV show.
A sci-fi show today has to do something seriously great to have any chance of surviving, and I really do not think anyone would argue that SGU has come even close to that. I've never watched Caprica but from what I've read the consensus is similar. "Pretty decent and had potential" just doesn't cut it anymore. The people making these shows have more than enough experience so that if they were capable of writing a great show, they'd be doing it from the start.
So in my most humble and totally non-instigative opinion, this show deserves its low ratings and high probability of being axed just as much as all those other shit shows out there. That those other shit shows survive because of the popularity of their genre is just another sad fact of the world, but not one that changes the other sad fact that SGU is really not that great or special or deserving of more attention than it gets.
OK, rant over, back to porn.