The new function will show you all your crop and tree mastery levels, all in one simple window. Unfortunately, most of my crop mastery levels are super low, making this page a bit demoralizing. As you can see, I usually just stick to Watermelon farming (Yum!), so my own My Mastery page is pretty boring at the moment.
I think it's great that FarmVille has adding more stat tracking features, but there are bigger fish to fry. What FarmVille really needs is some much needed performance improvements.