I have been to both buffets, and have been to both restaurants for dinner. I was not frum my whole life, and in my non-kosher days, I went to many Indian restaurants, especially in the "Little Indian" section of Manhattan (East 6th Street). I believe I know my indian food. To me, Shalom Bombay's food is significantly better than Dakshin's. Perhaps you went on an "off day." Also, as one person pointed out, Dakshin is in a very inconvenient part of town - 1st Avenue, between 63rd and 64th Streets, far from mass transit. By contrast, S.B. is in the heart of midtown. And, for a lack of a better description, there is almost a "trashy" ambience to Dakshin.
I went to Mosaica on Sunday, August 20, 2006. I was not happy with either my meal or the service. I had an 8:30 PM reservation. There were a few patrons still in the restaurant when I arrived, yet only one waiter/busboy to take care of them all. Needless to say, our service was poor. Glasses did not get filled up, to table wasn't cleared off properly, etc. And the waiter himself was a bit hard to understand, and spoke English in a somewhat confusing manner.
I ordered "seared duck breast." I expected to get a full duck breast, not a few small pieces of boneless duck meat. A side dish was advertised as "fried zucchini." I expected something akin to the fried eggplant one sees at meditteranean/mideast cuisine restaurants. Instead, I got deep-fried ultra-thin strips of zucchini, that tasted like generic, unidentifiable fried pieces (or perhaps like Durkee fried onions from the can) rather than zucchini.
I was disappointed. I went there to celebrate my 20th wedding anniversary. If this restaurant had a very good chef at one time, then to me, it's apparent that the restaurant is sorely missing him.