Tried Siri on my iPhone 4S a few days ago.
I was interested in how she works...
First I tried to enter "Status Update" on Facebook.
She was superb to understand my awful Japanese-accented English!
I'll continue asking her to enter sentences for me. It's great.
But I found a very important fact then.
She seems not so good at understanding my native Japanese... :-(
She can understand less than half of my words even I conciously speak slowly.
OK, I know I have to accept it because she might not be a Japanese. LOL!
Unfortunately functions about map are not yet available in Japan.
But I found Siri more useful than I had expected.