It got (gets?) faster in 2014r2. ListBox now keeps close track of what regions of the control are dirty and only redraws cells that intersect with those. It also got some small optimizations like detecting if there is a user-defined CellBackgroundPaint and optimizing for the case where there isn’t by drawing the row background in one go instead of cell by cell. I don’t know as any of that work helps with scrolling or resizing performance though.
Well I have some code that will really exercises it, to see if it introduces any unexpected changes/side effects … waiting for the beta!
Good news! Same here, I will run it though all the code I have. And I’ve got an early release rMBR with an underpowered graphics that will really stress it out!