grid vs layout based widget toolkits

grid only widget toolkits (like Cocoa Touch) vs layout based toolkits (like Swing or gtk+)

iOS Cocoa Touch, being only grid based, had to port all applica开发者_开发知识库tions when the screen resolution was upgraded (iPhone4) or enlarged (iPad)

If you could choose what would you use?

If I were designing for a platform where screen sizes could vary, I'd use a layout manager based toolkit. However if I could garuntee the same screen resolution and screen size, I'd choose to use a grid based toolkit, as it would mean I wouldn't need to think about all the logic that goes into making a layout manager based UI.