There's an assortment of differences - quality, features (DVI switching is a pretty rare thing, as is the ability to select analog or digital bass management on the 7.1 analog input), and customer support (you can pick up the phone during east coast business hours and only have to go through one layer of phone system automation to get to a person at Outlaw, plus the online support system, plus this forum).
I don't think I've seen a direct comparison between the 1070 and the Pioneer 1015, but I have seen a comparison between the Yamaha 2500 (acting as a pre/pro only) and the 1070's processor sibling the 970. In that
comparison , Doug917 came away feeling that the 970 was comparable to the 2500 for movies and somewhat better for music.