Okay, so, here's how it goes.
Has internal memory (100 Gigs)
Can use wireless controllers
Is Backwards compatible with some Original Xbox games
Comes with no internal memory, which means you cant save any game, or make an Xbox live gamertag or basically anything ( A separate 20 Gig hard drive costs about 70 dollars)
Have to use wired controllers (Unless you get a wireless receiver for the Xbox)
Unless you buy a Hard drive for it, you cannot play Original Xbox games
But, if you're doing what I'm doing and want the core system, and just buy the other things seperate so it's basically pro, it will come to about $340 BUT, I will only have a 20 gig drive, and not a 100.