There's the tmux -CC control mode support that was mentioned, which combines best from both. Leader key support that arrived in this version might enable even greater Tmux integration.

I like how easy it has been to manage Unix terminal keys without giving up non-US keyboard altogether. Other Unix/Linux terminal stuff like middle click/tap paste. Search is good. Hotkey window ("Quake" mode") is a fun one, but never seem to remember to call it. Contrast adjustment to tweak themes for readability. Smart Selection for urls and the like.

But I've been an user for many years, so hard to look at the experience through features.