If you haven't installed the controversial August Update for Windows 8.1 yet, you might want to wait some days. Guru3D reports that according to users, the August Update for Windows 8.1 is causing system crashes.
So far we have not heard of cases related to Windows 8.1, but for the updates released for Windows 7 there are indeed many complaints in official Microsoft boards.
As Guru3D points out, you can roll-back easily when system restore is active and you rewind to a previous restore point. So this might be also an option for all those who cannot wait but want to be sure to keep a working system.