Why is the Beagle/Panda boards so much more expensive than the Raspberry Pi? For one, they have a lot more parts on their boards. They're sold as developer boards. So it's unfair to just talk about the price of the SoC and say the rest of the price of the boards must be profit.
Also, Broadcom are subsidising the price of the RPi. I think TI also subsidises the Beagle/Panda boards, so maybe there's just a difference in how much each manufacturer subsidises their board(s).
As for performance, I want to see the benchmark results. The multi-issue super-scalar Cortex-A8 and A9 cores are reported to be able to perform 2.0 and 2.5 DMIPS/MHz, respectively. The aging ARM11 core only does about 1.0 DMIPS/MHz. So the claim that a 700 MHz ARM11 (~700 DMIPS) is only 20% slower than a 600 MHz Cortex-A8 (~1200 DMIPS) just doesn't "add up". Maybe something like a faster memory bus is helping it perform better on a certain benchmark.