I've used LyX for a very long time. It has the best graphical equation editor I've ever used: it natively supports all of the complex structures you'd want, can be used incredibly efficiently via the keyboard (e.g. tab-completion and tab-navigation), and is still incredibly discoverable via GUI.
In general, it's just a very pragmatic layer on top of LaTeX. I've done a lot of complex ad-hoc formatting in it as well.
I've used LyX for a very long time. It has the best graphical equation editor I've ever used: it natively supports all of the complex structures you'd want, can be used incredibly efficiently via the keyboard (e.g. tab-completion and tab-navigation), and is still incredibly discoverable via GUI.
In general, it's just a very pragmatic layer on top of LaTeX. I've done a lot of complex ad-hoc formatting in it as well.
Superior to LyX: fully WYSIWYG, no limitation on what it can do.