Moved up from a T6i, and I must say that the 6D Mark II was a fantastic upgrade. Not essential, but was great to have. The ISO improvement I really want to say was about 1.5 stops despite most people saying that it's typically one stop for the jump to full frame. Didn't have much trouble with recovering details from shadows in raw files and its supposedly inferior dynamic range. The articulating LCD was also great for getting low/high angle shots in Live View without getting down in the dirt or climbing on someone. I use this feature maybe about every third shoot, but I'm grateful to have it every time and was surprised to find out it wasn't a common setup on most cameras when I got into photography. The battery life was ridiculously great compared to the T6i: I don't take hour long photoshoots so I could make a single battery last me through a month if I wanted to. The centre cluster of AF points leave a bit to be desired, but I found myself using an even smaller centre majority of them anyway (closer to the edges often resulted in less than pleasing compositions for me), so I can't complain about that too much. One thing I didn't like about the AF system though, was that certain focus points were more effective than others depending on the lens attached. Not a problem if you're using first party fast primes, but using a Tamron 45mm f/1.8 caused the outside groups to be less effective (supposedly). It was a visual pain, but I actually didn't find much issue using the "lesser" points. Easily the best entry full frame DSLR from Canon!