I traveled in Air Deccan quite a few times. And I feel it a pretty good option if you getting at low cost. Check in facility is good. If you reach a bit early you will get quick check in. Check weight limit is pretty low. Internet booking in not too good. There could have been option for next day etc. You will find it difficult to find lowest fare by putting date again and again. But one can try some new travel site for searching low fares
While traveling you needs to buy the stuff available there, which is usually free in normal cost airlines.
Usually there help desk is pretty helpful. You can get required info.
But I think it is good deal against low cost air travel. One can travel considering the low cost compromising some facilities. But after the new taxes cost is sometime pretty high then expected.