I just brought home my brand new 2013 Civic SI w/o navi and with all-season tires. It is awesome! Pictures to follow. I traded in my 2011 EX, which was a great car. I wanted a car I would love and actually enjoy driving to work every morning. I think the performance is just right. It can pull uphill in 4th, 5th, or 6th gear. I've driven quite a few manual cars and this one has probably the best shifter I've ever seen and the clutch biting point is very easy to find. The gears are perfectly spaced. The power comes on smoothly and predictably. It has just the right amount of power. The ride is surprisingly good. It corners like few other FWD cars can. The addition of the I-mid system will have me reading the manual for the coming weeks. There is a lot you can do with it. I was considering a WRX or a VW GTI as alternatives. WRX's are pricey and don't get the greatest fuel economy, also AWD isn't really necessary in San Diego. I was close to getting a GTI until I read the message boards complaining about endless rattles and little things constantly going out, which I have very little patience for. I had a Mustang before. It was fun to drive when it wasn't in the shop. Plus this car is really a pretty good deal considering the performance and the refinement. I wouldn't change a thing about it yet, other than maybe some light tint to keep it cooler for the summer. The only issue I've had so far is that I don't like to drive fast ALL the time (especially in areas where it's easy to set up speed traps). And in the few hours I've had it, I've had at least 10 people either try to race me or tailgate me while I'm driving like 15 over the speed limit. But, that's not an issue with the car so much as other people on the road.
TL;DR: very well balanced car for a more than reasonable price.