Tyler Cowen's Ethnic Dining Guide
"Reputable?" - heck yes.
Of course, his taste may not always mesh 100% with yours - I find myself enjoying some places he rates only acceptable, and not enjoying some places he rates highly, but I think that's just me.
He is a far-ranging explorer, an honest and descriptive reporter, and an appreciater (like me) of holes-in-the-wall with genuine ethnic excellence. I use his guide two ways: to get suggestions on what to order at places I'm already interested in, and to identify places I hadn't known about before. I've gotten lots of great pointers from the guide.