Pros: Great mileage, quiet, looks great
Cons: Not always enough power
A great car. I bought it three months after graduating college and it's treated me great for the three-and-a-half years since. The trip meter tracks gas mileage from the point you reset it, and I usually leveled out around 42. That was with a lot of freeway driving, but still not a bad number. More recently mileage hasn't been quite as good--around 39 MPG over the last 8k miles. Not sure the reason, but it may be that the battery deteriorates. At this point I've put just over 60k miles on it.
My single biggest complaint about my car is that it doesn't always have enough power. I have a set of Yakima ski racks that I use during the winter, and the combination of the weight of a few passengers and their gear plus the drag from the racks themselves can make it a slow trip to Tahoe. Everything is fine on the flat stretches, but as I start climbing for miles at a time, the battery doesn't get a chance to regenerate and I end up running on four cylinders alone. I also noticed after one of these trips that leaving my racks on the car had a significant impact on gas mileage, which dropped by 5 MPG while I left them on.
On one occasion recently, I actually had some trouble getting up a really steep hill near my place in SF. I was trading parking spots with my roommate at the time, who drives an '07 Civic Hybrid, and he said he noticed the same thing on that hill after I dropped him off. That's the only time I've noticed real problems with power when I wasn't carrying passengers or gear.
All in all it's a great car. I haven't had any unexpected trouble with it and it's been relatively affordable to maintain. There haven't been any costs associated with it that wouldn't be in play with a gas-only car, but I wouldn't be surprised if that isn't always the case. Even so, my plan for the time being is to drive the thing into the ground--it's treated me well enough so far, and it looks good enough that I'm not itching to upgrade.