Since I'm sure it's the same, my Vibe gets about 30-34mpg depending on how I drive it. It's an automatic, 4 cylinder. I won't say it has a ton of power, but I don't have a problem passing people on the highway or anything.
One of the big selling points for me was the features it had at its price. It's got a 115V outlet up front, two cigarette lighters (one hidden for cellphone chargers/etc), a radio with RDS capability, and a metric {censored} ton of room. You can get it with an LCD screen and nav system, too, if you've got more money than I do. The passenger seat folds down flat so you can slide a 6x10 or 8x10 all the way in, too! (8x10 makes it difficult to shift though.)
Be aware that 2005 models are quite different from the 2003-2004 models. They got rid of most of the "bonus" stuff -- the roof rails, the second 12v outlet, and made the front end butt ugly in my opinion. In return, it's a little cheaper, and you can get a molded subwoofer for the back.
I'm at 73,000 miles on my 2003 and I've had zero problems that have required repairs done to it. Changed the tires, regular oil changes, and it's not let me down yet.