Alternative to x11/gnome3 ?

[Victor Sudakov]

Dear Colleagues,

What alternative to x11/gnome3 can you advise? 

I would like a more lightweight desktop environment, however it MUST
support switching between GUI users without logging out (like 
Ubuntu or Windows).

I tried Mate but it does not seem to be able to switch between users
without logging out (at least the display manager Mate comes with
cannot do that).

Thanks in advance for any input.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
AS43859