We have just returned from a 7/8 day booked through Ecstatic India. The whole experience has been truly excellent.
Arranging the tour was very easy with it primarily being discussed via WhatsApp, and confirmed via email, including some specific requests.
When we landed in India our Driver Ashok was ready waiting for us - he stayed with us the whole holiday, navigating the Indian traffic, making us feel very safe, and making suggestions from his vast experience of doing these tours, as to where to go for food, specific shopping and points of interest. Ashok is well worth asking for if you have the chance, although i expect all of the tour guides from this company will be of a similar high caliber.
At every location we also met a Local Guide, who would take us round each city or site, and provide us with the background knowledge we needed to understand a site properly. In general these were very good, with a thorough knowledge and a high level of spoken English, although one or two did take us to their preferred retailer of certain goods, where, taken into a backroom we felt fairly pressured to purchase very expensive goods (we didn't though!).
In particular our guide at Agra, for the Taj Mahal and Red Fort was fanastic and also Vinnie, who took us round Jaipur. Both had thorough in depth knowledge of their areas, a very high level of spoken English and took genuine care of us through the day.
We did find it a little difficult at times to make it clear we wanted to not only got to high quality shops, but also browse real Indian bazaars and mix in more - but it believe this is only for care of their clients.
All in all I doubt you can do any better than book a tour through Ecstatic India, and when we return we won't hesitate to use this company again!