[Rclark]

which system is capable of higher performance?

Imagine each system given its own proper seperate nutritional requirements for environment and treatment.

The open baffle system, say some very high quality OB speaker system with seperate OB subs, with it's requisite minimal bass trapping and diffusion, pulled far out into the room as required.

Or a sealed/conventional box system, say some very high quality tower system or monitor system with seperate sealed subwoofers, with tons of basstrapping, reflection absorption, ceiling treatment, isolators, the full nine.

I realize that one system might be more expensive than the other (although diy can be a factor), but given unlimited reign, so to speak, chosing the system for the system's sake alone, which one is superior?

[JohnR]

I think it's a bit of a myth that OB requires minimal treatment. I suspect it's more likely that OB has less of an issue with variation in dispersion pattern, but that can be accomplished with box speakers as well. In either case, placement in the room will have a very large effect; I think the first thing to do is decide what "floats your boat", then put them in the room and measure them, and than figure out what types of room treatment are needed (which will be different for different speakers and rooms).

That's how I'm doing it anyway