Well, i really don't see why they had to change the old interface. That said, I don't really mind either way. It looks just fine. I actually think they didn't get this whole Google plus look right. It just doesn't look "slick" like XF here does...
I rely heavily on Gmail to handle around 5 email accounts, categorise posts with labels, and star them re priority to handle - not to mention even I am using only a third of the huge storage.
I have no new design nor any link at bottom offering it.
I do use a gmail green theme maybe that's why.
I wish they did folders in addition to their excellent searches.
I have to set all my business mail to Archive, Label it with a message rule, then use the priority desktop function to display it bottom of the stack all together. All so my business stuff doesn't mix with my personal, webdesign and community mails when I'm off duty and don't want to be pestered by demanding clients after hours. Sheesh workaround.
Would be so much simpler to direct all on that email account into a folder I can check when I want to.