We had a Cobalt as a rental for a temporary delivery vehicle while one of ours was in the shop. I wasn't impressed, but it wasn't sub-par either. It was a good little econobox, and performed as good as anything else.
I've lusted after the Cobalt SS for many years, they're approaching affordability, and I think I may replace my Sentra with one.
My ex has a Pontiac G5 -- basically the same car. Base model 5-speed sedan. It's not that bad. Not the fastest car out there, but nice enough.
Right now I'm looking at a slew of '08s for under $10k. I just love the look of the coupe. Similar power(NA) to my DOCH neon, but 200# heavier.
John Heinricy frequently shows up at Detroit autocross events in his 2008 Cobalt SS in DSP. Generally is in top 5 of PAX