I used to think that before I tried using Qt Creator. Your project doesn't need to be a Qt project for you to use it. Make sure you enable the clang code model plugin. It's a bit slow but otherwise flawless.
Certainly willing to give it a try. I can say that I can't imagine any tagging system to be any better than CDT, so at best it may be comparable. Though if the system is comparable with an interface that's faster than Eclipse, it would be quite nice.
Having used both, Qt Creator is so much better than eclipse that it's not even funny. Of course, you first have to forget your eclipse habits and learn the equivalent QtC ones - in particular using the locator (http://doc.qt.io/qtcreator/creator-editor-locator.html), and the available refactorings (http://doc.qt.io/qtcreator/creator-editor-refactoring.html). Recent versions also ship with a clang backend for completion ; it also supports clang-format and clang-tidy natively, with inline fix-its that are shown automatically.
Opinions vary on QT Creator. I personally found it to be hostile to my desires. The little thing that made it unfit for my purpose was that, when I code for Cygwin use, I need my Windows editor to be configurable for Unix conventions, but QT Creator was not configurable to Unix conventions. Eclipse is configurable.
I believe if I had been making programs targeting QT, I might not have run into this issue. But I don't make that kind of program.