19.3% more cargo space in the Suburban.

With all 8 seats in use:
Suburban: 45.8 cubic feet
Odyssey: 38.4 cubic feet

Some other interesting cargo space factoids:

"The 2013 Honda Odyssey has 38.4 cubic feet of cargo space behind the third row.  The third row seats fold into the floor, which increases cargo space to 93.1 cubic feet. When the second row seats are removed, the Odyssey has a total of 148.5 cubic feet of cargo space."

http://usnews.rankingsandreviews.com/cars-trucks/Honda_Odyssey/Interior/

"The Chevrolet Suburban can hold a total of 137.4 cubic feet of cargo, which is outstanding for the class. It can fit 90 cubic feet of cargo behind the second row and 45.8 cubic feet with all seats in use."

http://usnews.rankingsandreviews.com/cars-trucks/Chevrolet_Suburban/Interior/