Considering the 7cu should be like $20 more, get it, especially if the compressor hump in just a corner, not front to back. its probably about 7.3cu and you'll fit 4 kegs plus CO2 in there easily.
Because you don't wanna be like me and have a 3 year old keezer being replaced already because I don't have room! Just got my 14.8cu chest delivered today.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10