I've created a desktop app using QML (the model is written in C++) that looks pretty good in my opinion[1]. I second the out of the box desktop integration, Qt Quick components should look and behave more like native ones. Although they're very easy to customize so it's not too big of a problem. But definitely something to consider if Qt wants better adoption.

[1] https://www.get-plume.com

There still isn't even a native way to make text nodes in a custom widget. It's been 14 years.

I tried to write a basic serial console app using QtQuick some years ago but the functionality was just too anaemic. I don't really understand how you can write a serious GUI app with QtQuick/QML. If it's just very basic controls, sure. As soon as you need something slightly complicated it totally falls down in ways that QtWidgets don't.

Also the scoping rules of QML make no sense. Children can refer to parents which totally breaks encapsulation.

I love Qt, but QML is meh at best.

Qt Design Studio not enough?

Qt Design Studio is buggy and heavyweight. It lacks integration with Visual Studio, has a bad integration with Qt Creator. It doesn't produce clean .qml files. Qt Designer (the one used for Qt Widgets) is better in those regards.

Anyhow, this might be a controversial opinion, but the best experience I've had with WYSIWYG UI designers was with Netbeans Swing Editor and VS Windows Forms Editor. The IDE integration was seamless.

I only saw demos of it, though it would be better.

Yeah those are great, although I would then add classical VB, Delphi and C++ Builder as well.

Can it even do basic forms by dragging and dropping of components?

I recently tried and failed. It was either doing absolute positioning or failing completely - for example dropping components onto grid would just place them into cell 0,0. There was no way to design form with mouse.

I used a lot of different UI designers in the past and all of them were heaps and bounds better.

As sibling points out NetBeans Swing designer (with Matisse/GroupLayout) is the best, along with VS WinForms (although these tend to be non-scalabale)

in which ways is the qml desktop integration lacking?

If you create a sample project with a list view, you can scroll that widget by clicking the mouse on the background and dragging it (a reminiscence from touch based interfaces). The example projects don't look native but look like a mobile app inside your desktop. Windows themed button sizes don't follow Windows 7 desktop guidelines out of the box.

Sure that if you put the extra effort you can make QML look native, but it makes you wonder if desktop is in fact a goal for the framework.