To follow up on my own comment... I agree that in terms of raw SPL capability, the 600 is more than my room needs too (14x20x9).

However, in terms of low frequency extension, 2 500s wouldn't have the same low-end capability as 2 600s (or 800s), and I do really enjoy the low-end of the 600, and imagine I'll enjoy the lower end of the 800 even more. I suppose if I turn out to be completely wrong I can send it back... there's always that option.

Epic 80-800: HG Cherry