You might want to check out this site on the Internet. It has a comparison table at the bottom of the page.
http://www.xbox.com/en-US/hardware/compare101.htm?WT.svl=nav
I don't know much about these things, but I do know my son has also been looking. He says the XBox 360's have an overheating problem that the manufacturer has not been able to correct as of yet. The "arcade" version might be an attempt to fix the problem.