It IS Oo-kei. There is no argument. Like Tori is Toh-Ri. Its Japanese, and Japanese use Romaji (the style its written in) as a Phonetic writing, like hiragana or katakana. Each syllable is pronounced.
But then, technically, most people'd say Tori wrong, because you use an R in the middle, when its more like a mix of R and L, and not a great deal of Westerners can pronounce that...