The beta build 12B17 is reportedly having no issues. The 10.X.1 OS X updates are usually maintenance related updates and are let out soon after the initial 10.X.0 release. No release note shave been included yet in the 10.8.1 seeds.
Apple is asking developers to concentrate on Active Directory, iCal, Microsoft Exchange in Mail, PAC proxies in Safari, SMB, USB, and WiFi and audio when connected to an Apple Thunderbolt Display.
[Source: 9to5Mac]
