I've been sitting at 5.5" for well over two years now, so there is no real adjustment period for me with the 6+. I enjoy web browsing more on the 6+ because it offers true landscape full screen mode, which means more real estate being used for browsing.
I've also had a 6" HTC One Max and 6.3" Galaxy Mega which were a bit too big for me. So that 5.5 - 5.7" size within the existing Note 4 / 6+ footprint is my sweet spot.
One thing the 6+ has over my old Android phone is it doesn't simply blow everything up if the apps are optimized for the devices. But since I've dealt with it for so long, the blown up apps don't really bother me. I do sorely miss the multiwindow multitasking though. OS Experience on Cydia can't come soon enough. 🙁