Due to the service, I will NEVER go back. I love Indian food and have been to quite a few places in the valley. Chennai's food was average... when we actually received what we ordered (dinner service).
Pros:
-Relatively fast turn around following ordering.
-Food was pretty good, if nothing to write home about.
Cons:
-Servers had no idea what was on the menu. They came back twice to ask if "that 'chinna' thing" was a soup and then seemed to point at the menu at random, asking "is that it?" Channa masala. It's a pretty ubiquitous dish. And I can show it to you on the menu if you hand it to me.
-Of the 6 dishes we ordered, 2 came accurately, 3 were entirely inaccurate (e.g. chaat when we'd ordered a curry dish), and 1 never showed up at all.
-They tried to charge us for dishes we didn't order in addition to those we did.
-We had to ask the waitress for water 3x before she brought it.
If you're going to go there, go for the lunch buffet. The less you have to interact with the servers, the better.