Just moved into a new office round here (Cremer St) and we've been trying out the Vietnamese places in order to find a favourite.

Rankings so far:

1. Song Que (very nice food, friendly hungover waiter)
2. Mien Tay (good food but shockingly slow service)
3. Hanoi Cafe (cheapest so far but it turns out you get what you pay for)

I've also been to an amazing BYOB place a lot further up, past Haggerston station, but not sure they're open at lunch and it's a bit far to go anyway.

Does anyone have any recommendations?