Dan Stenmark a former Apple employee shared the following:
cornerRadius is notoriously nasty on the GPU. There are situations when it really is the only option, but it should be avoided when possible.
Also, I’ve actually been moving away from sharedInit() and over to putting my view setup code in willMoveToWindow. While it does mean you have to write the code in an idempotent way (in case said view is repeatedly added and removed), you no longer have to muck around with multiple init methods.