My objective opinion that i'd look at the Si vs. the Mazda3. The Scion tC feels a bit too....out of touch to be a sporty car. Its hard to describe, the shifter could be better, and you can feel its heft. It does have a lot of potential however and it is a great bang for the buck, along with Toyota's reliability and resale (not like Honda is that far behind anyways). The Mazda, however, will give you a whole fleet of options and is very well priced. It also feels and looks better to me. If it was Mazda vs. Civic i'm not too sure what i'd take. However i'd take them both over the Scion.