This++
I've used Qt for desktop apps as well as apps on Embedded Linux. I've even used it with a Lua wrapper API that made development even easier.
Is it a bit bloated? Yes. But unless you are very constrained for memory and flash space it should fit in your embedded system. They also have a way for you to select which components you want to compile for your target, allowing you to control how much of the bloat you actually use. :)
I've moved back and forth between QT and raw C++ a couple times. QT might be "bloated", but so will your proprietary program if you create something non-trivial (i.e. a cross-platform application with networking support, threads, font rendering, etc). The bloat has never bothered me that much, but what did bug me was when Digia took over and kind of mangled the code base a bit. It broke a lot of my code, I got frustrated and could not easily find the old version of QT to work with. I think this is a move in the right direction at least...
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.
the problem is not this . the main problem with Qt is , it is not standard C++ library (or framework or toolkit or whatever you name it). All the moc crap ! made it useless .(yes I know , with hacking(or with little changing) it you can use it with other library like boost or anything .
but in my mind this is not right way to do thing !
for example look at which one google chose for chrome in linux (before aura).Google chose gtk++ (which is much inferior than Qt in any ways , and as far as I am aware Qt licence was not issue with chrome) , but it is standard !
tldr; I like Qt, and I'll use it again.