Screen sharing in OSX El Capitan
I use a standard VNC client. Once you have Screen Sharing enabled on the System Preferences you can access your remote Mac with any VNC viewer/client application.

More precisely, on my Mac I use the outdated Chicken (still working fine on El Capitan, though) and for the iPhone/iPad there are also plenty of choices on the App Store.

NOTE: Make sure that you set a password on the Screen Sharing preferences.