plus the Xbox is a PC... it's very easy to program for something that is available technology... the PS2 is not a everyday appliance... has special chips and special coding...
your Xbox is a celeron processor with a shared IDE interface for the DVD-ROM and HDD. I think even Pheonix makes the BIOS for it... pretty straight forward I would think... I plan on tinkering with it later in life...
I'm partial to my PS2... always wanted to code on my PSX (PS1 was known as a PSX in the day) but it was such a hassle.... now I can FTP an ELF over and test within second of compiling it.. no CD burning or special carts to work with...
The Xbox is more PC than anything else on the market
PS3 Slim 320GB
PS2 v11 exploit w/300GB Maxtor
PS2 v10 exploit w/80GB Samsung - Network Games
PS2 v10 exploit w/60GB Samsung - Network Games
PSP 1001 3.52M33 w/10GB total storage
NDS DSReal 4GB