Good car for the price, at least for right now. The only thing I've heard to recommend against it is that Scions are designed for a much shorter usable lifetime than most cars (120k-130k as opposed to 200k+).
In my opinion, though: If you're looking for a cheap, fun, practical car, and if you have no quirky preferences with respect to style or brand, there is simply nothing else on the market besides the Civic Si. It's a little more expensive than a Scion tC but, dollar for dollar, it really makes everything else look like a good effort at best. I have enough to say about that car in relation to its peers to fill a screen or two, and I can discuss it at whatever level of detail you'd like. But for now, let me just say that if there is any possible way you can save up for it, that car is the way to go by a long shot.