You may have to wait for a seat at one of the long communal tables, but that just means it's good. These trendy, funky restaurants popping up all over London serve good pan-Asian dishes at reasonable (for London) prices. Once you've selected a dish from the extensive menu, the waiter will punch your choices into his/her hand-held keyboard, magically sending your order into the kitchen. The food is served to you when it's ready, not necessarily at the same as others in your party. But don't sweat it, man, everything's cool - you're at Wagamama, baby! Eat up!
Yes, this place is so hip, it even has a cool website... Check it out.