I recently made a short last minute trip to BR Hills (this is the entrance point), just wanted to share some information regarding it.
Drive time from Bangalore was about 4 hours and we stayed in the wonderful JLR property - K Gudi Wilderness Camp. While I had booked a standard room (about Rs 3500 per night per person), once we reached the property we upgraded to the cottage. Not that the standard room was bad, it was great but once we were there, paying that bit extra for the cottage was totally worth. There's plenty of birding opportunity within the property and staying in the cottages allows you to be in the thick of things. There are a few bird baths in the Golghar (dining area) and this is the centre point of birding activity in the lodge, especially on sunny days. Unfortunately, when we were there (mid November), it was a little cloudy and not the best conditions for birding within the property. For birding in general, December is a better time since the migratory birds start arriving there in November.
Generally we have a perception that wildlife in Karnataka is quite expensive, however paying 4K per person including 2 safaris a day, all meals along with a stay right in the jungle, I feel it's brilliant! When it comes to big cats, you need to be incredibly privileged to see one in these environs but it is teeming with wildlife, great birding activity in a unique habitat at the confluence of the Western and Eastern ghats.