I've been wondering the same thing. Of course I'm thinking "when I win the EP600 but have to downsize, what will I go with- a 350 or 500". Hmmmm. If I was going to start out fresh, I'd go with a 500 over a 350 but that's a pretty easy decision. It's the upgrade decision that's more difficult. I just sold my HSU STF-2 and bought an SVS PB-10. Same size-10", but the amp is much bigger in the SVS. Guess it will make some difference. We'll see.