I recently had an opportunity to fly Air Deccan again after some gap. They surprised me with a decent flying experience. Do not look to them for inflt food (even for purchase) or entertainment but they do seem to have an increasing network, better timings and stabilizing operations.

Kingfisher had a bunch of delays around the days I was in India (Jan 2006). Jet was still the best in handling delays but Air Sahara was not too bad. SpiceJet seemed to have issues with limited fleet size to react to ATC and weather delays.

All in all, all the carriers seem to have improved a lot.