Shawn, it was a hard decision. I kept going back and forth from getting 2 500's (to help even out response) or worry about upgradeitis in the future, and just get the 600. I've heard the 600 will play lower, and I think the bigger enclosure has to add to the performance, plus it has another 100 watts over the 500.
My room is very big, and in reality I don't have to much of a frequency change from seat to seat, so I decided on the 600. I will be adding some additional column bass traps to the rear corners over the next few months.
