I stayed at the Hotel Marine Plaza on Marine drive a few weeks ago. www.hotelmarineplaza.com
The hotel and staff were very friendly. They offered afternoon snacks in the room and the room/bathroom were very clean. It is located right on Marine Drive.

One negative: The air conditioning control was poor. I could not achieve a comfortable temperature. When on, it was too cold; if you turned it off, it became too warm.

Also, there is a nightclub in the building which can be loud. Ask for a room away from there if you don't want to hear the music.

As do many hotels in India, they have separate rates for foreigners and Indian residents.