I used this mobile for almost 15 days and I was very satisfied with its performance I also used samsung galaxy note 4 and their was a clear improvement over it.
Build quality- The primary reason for me to hate samsung phones was that all their phones were having same design and the quality of plastic was horrible. But note 5 is now one of the best design I saw in 2015. I was very happy with its build quality.
Camera- Samsung was always producing good cameras and note 5 is no exception. It gives very nice and vivid pictures in day light and was also producing decent pictures in night also.
Sound quality- The sound quality was decent but not the loudest one I have also used htc one m8 which was more lounder than note 5 but it was sufficient to listen to music.
Battry life- Battry life was also good as it use to give me around full working day with medium use but if you are a heavy user then you have to charge at night.
Screen quality- In my experiance the screen quality was one of the best in 2015 with vibrant colours.
Gaming- gaming was perfect whatever game you through at it it was able to handle it with ease. There were no lags and you will have nice experience while gaming.
Overall its one of the best phone produced by samsung and I will not hesitate to recommend it to anyone subject to that the features of stylus is helpful to you.