iOS 8.1.1 has been released.  We have tested this patch and found it appears to fix the performance issues, especially with older iOS devices that have plagued it since iOS 8 was first released.

If you rely on your iOS device for mission critical applications for work, we recommend NOT upgrading to iOS 8.1.1 until after classes end. Many application developers are still struggling to get their apps to behave correctly in the new iOS 8.
  
Any user who has non mission critical iOS devices may now upgrade to iOS 8.1.1 if they so choose.