I've run high performance code on QT without any problems. The DLL bloat is a bit annoying though there are ways to reduce the size of them. However, QT makes

I've run high performance code on QT without any problems. The DLL bloat is a bit annoying though there are ways to reduce the size of them. However, QT makes threading and concurrency so simple (and cross platform) that I wouldn't go with anything else. We just switched our system to Linux to avoid Windows' awful file IO and the code compiled (as expected) without a single change. Love it.