I might be in the minority, but there is nothing I prefer about iTerm2 vs terminal.app. In fact, I think text color representation is much more accurate in terminal. And I don't need window-paning / split screening since I do all of that in Emacs anyways.
I've found Terminal to be perfectly adequate. Back in the 10.2 days I had to use X11 and an xterm since the transparency thing was murder on my GPU, but ever since Terminal with very few tweaks has been great.
Considering it's built in, it's light-years ahead of the junk that Windows calls a shell window.
There is nothing "accurate" at all about Terminal's colors. If you take a screenshot of the terminal next to your settings window, you'll find that the colors in the terminal don't match the ones in your preferences at all, particularly if you have a dark terminal background.
iTerm 2 doesn't do this. It's the "accurate" one. If you prefer your colors the way Terminal mangles them, you'll have to set them that way. :)
That's odd since I find iTerm2 much better looking in terms of color representation. Plus TrueColor support in nvim look amazing. BadWolf theme never, nowhere, looked better...