Two main issues have come up for those who have updated to OS X El Capitan:
The Sims 3 – Those playing the disc version are experiencing the disc authorization error. This can be fixed by uninstalling your most recent EP/SP and downloading and installing the digital version through Origin. Instructions here.
The Sims 4 – Those who have Macs with a NVIDIA GeForce GT/GTX 6xxM 512 MB graphics card don’t seem to be able to properly play. The game is glitching, crashing and freezing. This only affects the GPUs with 512 MB VRAM.
There are threads on the officials and AHQ related to this. The Sims 4 El Capitan thread has been stickied and SimGuruJanitor has posted in it. As usual no other acknowledgement has been made so all we can do is hope that EA are still paying attention to it.