if you have a honda civic now, you're pretty much getting the same thing when you get a tC. ive owned a tC since 05 and has been great, never had any problems. gas mileage varies on the driver. i can get as low as 22mpg when im driving hard and fast. or as high as 30mpg when i take it slow and easy. the civic should be getting you around or over 30mpg.. of course though the tC has alittle more room since it has a longer wheel base (from front to rear wheel) the rear seats recline back and fold. and it is a hatchback so you can get bigger things in and out of the "trunk/hatch." i myself managed a widescreen tv STAND in the back somehow. performance wise is realitivly close to the civic, has alittle mor power and torque, though the tC is a little heavier. of course has the all glass sunroof its known for. accelerates good on the highway when you need to pass someone (some people find that good???? I dont know) handling is great for the cars weight. and then theres the performance/aftermarket scene the tC has. plenty of ways to customize the tC performance and visual wise.
its a great car, i like it, have nothing bad to say about it.
good luck though