Apple - Several users simultaneously on a Mac mini

Not sure how it was 2 years ago when this question was asked but I confirmed that this work out of the box for me now.

Mid 2010 Mac Mini running OS X Mavericks 10.9 Client machine tested: Windows 7 Pro using TightVNC Viewer, iPad using iTeleport.

Both client devices were able to connect to Mac Mini via VNC and log in to different user accounts at the same time.

On every VNC session, it will show the mac login window which user can choose to access specific user accounts.

Though I would agree that it might be using up more resources when multiple users are connected at the same time, furthermore using for development.

Yes, it is possible. But both computers must be running Lion.

In the Host Mac go to System Preferences > Sharing > Screen Sharing and enable it. Check the preferences, too.

In the Remote Mac just hit Command+K and type vnc:// and the IP address of the Computer.

Yes, you can do this in Mac OS X 10.7 and later. Just set up an account for each user and enable VNC (System Preferences => Sharing => Screen Sharing).