We visited (3 weeks) a little piece of India in July 2003 : Delhi, Ladakh, Zanskar, and Agra.
It's a very constrated country. We saw the polluted, grey, hot and wet Delhi, and after a small flight, we landed to Leh, - Zanskar - under the blue, pure and clear, and with alpin fresh air. The dull cities was now wild and bright colours villages.
Travel agency or buy ourselves ?
Facing the hard task finding out an indian internal flight from France, we booked throw a travel agency. It was our first travel with an agency : Nomade.
We really appreciated the in-site and France agency's arrangements (slides, explanations, ...). But, being used to the freedom of travelling by ourselves, we did not fit a lot with the group (8 people). Plus, the group attitude is often less respectful toward the visited country than 2 isolated people.
If you want to go to Ladakh - Zanskar by yourself, you can arrange your trip in-site. Just think to book your flights before.