I'm still using and evaluating the three apps you listed, qtFM, Qupzilla and Juffed.
Qupzilla and QtWeb are both contenders for web browsing. Both are fast and stable, even if lacking the features other web browsers already have. Fast and stable are as important to me as web privacy is. Right now, it's hard to choose a winner among the two, although Qupzilla is edging out QtWeb due to its ease of installation and better features. QtWeb is delivered as a single zipped file.
Juffed is definitely a fast and configurable text editor. I like it much more than Geany.
I'm also still evaluating qtFM versus SpaceFM. I know that SpaceFM is not a qt app, but it is better, to me, than PCManFM ever was. My only beef with Thunar is the gvfs network mount thing. To recap, after each login, the first time Thunar is called, it takes up to two minutes to appear. After it finally does appear, a copy appears about a minute later. It is "waiting", or something, on Gnome's virtual filesystem network mount to register. The behavior can be curtailed by editing the system file /usr/share/gvfs/mounts/network.mount (as root), and changing the AutoMount option from true to false. However, any system update to gvfs overwrites the changes to the config file, which necessitates having to make the change, once again. Or, living with Thunar's startup quirkiness. Unfortunately, this behavior from Thunar goes back a number of years.