I upgraded from a 4 classic to the 6 classic and it does charge faster, and the battery does seem to last longer, the screen is better, but the Samsung Health Sleep does not recognize when I get out of bed that "sleep" is over like it did on the 4. In order to get Health Sleep to sync the sleep data I have to go into sleep on the watch, then it uploads to the watch. Everything else syncs correctly, just not sleep.