Anyone who has worked with Multithreaded PyQt4 apps? I was just wondering if the inbuilt signal/slot mechanism coupled with QtThread of PyQt4 framework has any benefit over the standard Python threads (which are designed in my code to handle the UI components in a thread safe way offcourse) using event driven async callback.
I am looking for any major speed or security concerns, any specific run-time exceptions or edge cases. (The UI is quite complex hence a re-write at a later stage would be very counter-productive).
Thanks.
Edit: I realize this might mean replicating some of the already present PyQt core functionality but it is ok if it allows more flexibility within the app.
There's no point really using Qt/PyQt if your're not using the signal-and-slot mechanism and rolling your own event loop. Basically, you'd be reimplementing the core of the framework itself. But I'm guessing this is not what you're asking about.
It would be nice if you could clarify your question a bit, (because of which I've had to make a few assumptions)
but here's the deal:
I think you're a bit confused about what the signal and slot mechanism does. (or maybe not, forgive me for reiterating some stuff that might probably be obvious to you). 
The signals-and-slots do not implement threading for you (so the question of using signal/slots having any benefit over standard Python threads is moot)
You're probably assuming that the signal-slot mechanism is multithreaded, and that a slot when called by a signal, executes in a new thread. Well, this is not the case.
The signal and slot mechanism in Qt runs in a single event loop in Qt (implemented by QApplication), which itself runs in a single thread. 
So signals and slots are not replacements for multi-threading in any way.
If there's a slot that blocks, then it will block your entire application.
So any blocking I/O or time intensive functions should ideally be in a separate thread from the UI, and your slots should start execution of these threads.
Now whether to use QThread or standard Python threads to implement your own threads is another issue, and it's been asked on StackOverflow before, but I tend to use QThreads for Qt apps.
So if you have a button, and you want to start a file download with the Requests library when its clicked, you'll connect the clicked signal of the QPushButton to a slot say for example downloadButtonClicked, and that slot would start a new QThread which would take care of downloading the file using Requests. You can further connect the finished() signal from the QThread to know when the download is complete and to update your UI
(I'll add a code example if this is indeed what you're asking about. So please clarify your question)
PyQt4: Conventional multithreaded UI over Signal/Slot mechanism?