I'm not exactly sure why car2go has had so many reviews but I tend to disagree as I LOVE it! It's one of those things you are almost scared to rave about because it might become impossible to find availability.
Unlike other car rental services you don't have to return the car where you left it. This is Ah-maze-ing! If you drive across the city like I do, it's less than half the price of a cab and way faster than that dreaded King street car.
My pointer to you is to download the app because it uses GPS to tell you where the closest cars & park spots are. It's brilliant. You know what else is brilliant? Ripping around in a go-cart! Those things are fun. They don't have enough power to go very fast so you don't have to worry about speeding but be warned, they slip around like crazy on the icy streetcar tracks.
The only reason it doesn't get a perfect score is because during peak times it can be hard to find an available car, even with the GPS enabled app. As well, I imagine if you drive outside of the city often, that could be a bit problematic as well. However, if you are like me and just need a car occasionally to zip from point A to point B, then this is a great option!