TeXStudio is also what I recommend to LaTeX beginners and intermediates. Otherwise, VSCode with LaTeX Workshop works great. It has the huge advantage of being a general-purpose editor, since I don't like the idea of having one IDE per language.

Other than that, the second part of "integrated pdf viewer with (almost) word-level synchronization" is not really TeXStudio's achievement, if they leverage SyncTeX [0] for this.

[0]: http://www.tug.org/TUGboat/tb29-3/tb93laurens.pdf