A feature that I wish Gmail would copy from Outlook.com is the ability to auto delete emails after a certain time. I have all email tagged with the intelligent Social updates category delete after three days.

I use Gmail and Outlook to manage different email accounts. The Outlook.com inbox has smart categories which are similar to these new Gmail categories/tabs. Instead of tabs across the top like Gmail, Outlook.com has Quick Views on the left hand side which activate the category filter.

Hopefully Gmail will allow you to customize what is filtered by their smart categories like Outlook.com does today.