I hadn't seen Stack before. Have you used it & would you recommend?
However the template system is in XAML which is fine if you're au fait with that but can be a bit fiddly to get what you want.
The only other issue I have with it is that the full version - which is definately worth the money - is distributed via the windows store which forces you to have an account with Microsoft. Overall though, excellent.
The PowerToys tool lacks many things, including multiple monitor support, tabs, etc
Agree 'FancyZones' is pretty undercooked at this stage. Promising though.