What improvemets does PSP Go! offer over PSP 3000?

[Dgc1808]

More compact
No UMD Drive [this is a plus or minus]
Greater Storage option. [with a 16GB Go, you max storage possible is technically 48GB. If they ever release a 32GB Go your max would be 64GB]
There's talk of in-game XMB from sony but that hasn't been confirmed.