While not the same car but a long stretch, I had a 2008 Civic Si. At the time the Si Had the K20, or the 2.0 VTEC engine (vs the TSX 2.4). The later Civic Si had the same engine as the TSX, the 2.4. I briefly considered getting on when they came out (or a TSX).
The car will be very reliable. Sure the old "hondas live forever" thing is out there, but the K20 and K24 motors are very reliable. In one form or another the K24 powered many vehicles so parts are all over. Specifically the Element, CRV, and Accord. Of course there are some differences with the TSX engine. I believe the variable timing was on the intake and exhaust sides VS maybe just the intake side. This gave it around 30-40 extra horsepower and that sweet sweet VTEC sound and engagement.
Now, heres a bit of a rub with the TSX. While a torque'ier' motor than the K20, it still likes to REV. So the issue comes in the form of the transmission. The 5 speed auto and its gearing makes the TSX feel sluggish. It still has the "manual" option for shifting, but its still not enough to get the most of the 2.4L. I'm not an automatic "hater" by any means, but the pairing just doesn't feel right IMO with this car.
That said, it will still be fun, and very reliable. If you like everything else about the car a manual, or a TSX V6 may be a better bet.