I haven't and can't upgrade yet but I have read this

Source: http://www.yurdigital.com/forum/software-forums/vue/only-few-days-left-vue-10-way

Toward the bottom of the opening post

"Up to 30% Faster Rendering Speed - I can verify this. The Vue 9 scenes I loaded were actually rendered faster, due to the significant internal optimizations made by e-on."