I tried iTerm and then Hyper, and didn't really see how either benefited me over Terminal.app so I stuck with that. But these days I do most of my development work inside Emacs, and the vast majority of my Terminal.app usage has been replaced by either a first-class Emacs plugin (like Magit[0] for git) or Eshell[1] within Emacs.
The main thing for me is split panes, but I don't primarily use an editor like Emacs that can do split panes, and I never bothered to learn tmux (iTerm does have neat tmux integration though)
Ah right, split panes are pretty nifty. Very easy to do in Emacs and convenient too. When I'm using Terminal.app, I just use two windows and place them side-by-side if needed. But most of the time a single windows suffice for the small things I'm doing.
> I have been using using Hyper kinda since the beginning and eventually switched back to iTerm because it's way faster if you use it all day long.
This is how I feel about Sublime Text vs Atom. Every time I try to switch to Atom, I run into this problem. The slight sluggishness gets increasingly annoying the more time I spend using it.
I was using Atom for a long time and performance got better over time. I like to use OSS so Sublime was not an option for me.
Once I went back to vim, though, I was impressed again by its performance.
It's a pity that electron still has some trouble with performance. Slack, for example, does not make me happy. Visual Studio Code, on the other hand, is fast and is written using the same platform so there must be a way to do it right.
This was exactly my experience. I didn't see any benefit over iTerm 2 and the performance was just sluggish enough to be subconsciously annoying after awhile.
[0]: https://magit.vc/
[1]: https://www.gnu.org/software/emacs/manual/eshell.html