I'm looking to upgrade from an older 10" Audiosource subwoofer in my den (which is a converted garage). The listening area is about 12'W x 20'D ... with the sub in the front corner. The unit will only be used for home theater - not music. The receiver is a Sony STR-DE935 with DCM KX-7 Series bookshelf fronts and center. Now the tricky part: Which one is the better value for the money? The reason I ask is that I can purchase the Sony for $179 (delivered), but can obtain the Audiosource in a straight trade for an unused set of Mission 70 satellites that I own. I've heard good things about both subs, but have not seen many direct comparisons between these two. Recommendations?