Linux-based pfsense?

Note: I'm a Linode customer but this isn't Linode-related. I just thought that you folks would be capable of answering my questions.

I moved to a location pretty far from the local phone company CO. I'm wary of Comcast's policies and practices, so I'm considering using two DSL ISPs and aggregating them for my house. The total bandwidth would be about 3.0/768. The question now is how to perform the aggregation without spending $1300.

I found out about pfsense, but I'm really more familiar with Linux so I'd prefer to stay in that world if possible. Do you guys think pfsense is the best bet for what I want to do, or should I look into Linux alternatives?

Thanks!