After a long wait , the Indian users are able to upgrade their Android version in Samsung galaxy note 4 to Android Marshmallow ( 6.0.1)
The over the air (OTA) update file size is somewhere about 1.4 GB and its takes about 25 minutes to download even in a 100 Mbps connection. For this size of file , this should not take more that 2 mins but not sure why this is taking more time to download.
After upgrade, now my phone looks bit faster and the page transition animation have become much smoother. Looks like , the power save mode now restricts almost all background data access and this impacts the widgets that are relying on external data.
Overall the upgrade seams to have a positive impact on battery usage and performance of the phone.