tab menu + side panel – how to organize menu and "context menu"

I have a dashboard, with tab menu (tabs over the content) and a side panel with a vertical menu.

My question is: I would like to make one menu (tab or side panel) as first level menu and the other menu for options inside a specific context.

for example:

On my tabs i have three menus (users, analytics and categories). After that i click over one of those, i.e users, then my left menu will show options related with users (manage, audit, etc). I could do as well the opposite, at the left menu, users, analytics and categories, and as soon as i click on users, i get three tabs over my content (manage, audit and etc).

So, how to decide, which model is better? What i was thinking as decision point is, which menu can have more elements, since too many tabs don't looks nice.

any other tip or idea?