Hello, 
first of all I have to congratulate you on the MATE desktop. I was surprised when I first used it. It's intuitive, quick and functional.
I'm thinking about installing it on my Desktop, but I have a few questions about the panel.
In the picture you can see a large panel in KDE. It has multiple rows and hides automatically. Note the quick-start and the notification areas. This turns out being very practical. Can something similar be achieved with MATE?
As KDE has been responsible almost every time my desktop "hung" or the computer slowed down, I'm looking forward to getting away from it in the near future.
On my wide-screen notebook I'm already using MATE. I placed the panel on the left of the screen (vertically). There are some inconsistencies and drawbacks, though. For instance, the default clock simply writes the time and date from bottom to top in a 90° angle, which is okay. The task-bar (showing the running programs) can't do so, unfortunately. You either get to see only the icons or you make the bar wider and have the notification icons growing, instead of arranging in columns/rows.
Thanks for your time,
LC