I thought QTCreator was a really nice IDE as well. I am thinking about using it to develop my GUI tools for my engine when it comes down to that point since the only tools I've developed were for Windows using c-based winapi's back in high school haha... I had a few gripes I have with QTCreator. I haven't figured out the licensing, or what kind of royalties I'd have to pay Nokia if it came down to me producing a commercial produce. From what I've seen from tutorials, there seems to be quite a bit of OpenGL wrappers involved with QT. I'm not sure if I could link to standard libraries that are already installed on my system that weren't built from QT.
QtCreator does not force you to use Qt. If you don't, you are only bound to the license of the compiler you use (if you use a bundled version, usually MinGW derivative or MSVC; otherwise whichever compiler you chose to setup).
If you use Qt you can buy a commercial license or use the LGPL license (see here). Since I'm not even sure there is a viable Qt 5 build which links statically that seems to be almost a restrictionless license.
Also, whichever way you go, Nokia does not factor in there at all. Qt is now in the hands of Digia.