WinForms layout managers are a pain to work with in the designer, though. It wasn't written with them in mind - they only showed up in .NET 2.0 - and it shows. Dragging and dropping things doesn't often do what you want them to do, and sometimes things just disappear, and you have to dig them out from the control tree.
Data binding is better in that regard, but once you start doing complicated nested data bindings, it's rather tedious to do it in the designer (because you can't just bind to "A.B.C" - you have to set up a hierarchy of data sources).
Worse yet, you start hitting obscure bugs in the frameworks. Here's an example that I ran into in a real-world production WinForms app ages ago (side note: I wasn't an MSFT employee back then, so this was an external bug report): https://connect.microsoft.com/VisualStudio/feedback/details/...
Having said all that, the aforementioned app was written entirely in WinForms, using designer for all dialogs (of which it had several dozen - we used embedded controls heavily as well), with dynamic layouts and data binding throughout. And it did ship successfully. So it wasn't all that bad. Still, not the kind of experience I'd want to repeat, when I can have WPF and hand-written XAML.
