Milen Dzhumerov with an extremely detailed and well written post on how the sync works in the todo list app, Clear. They use iCloud file storage rather than Core Data sync to sync a series of transactions for the app state rather than the end result data itself. It's also a great write up of exactly why this is a hard problem.
In response to Florian Kugler's article that I linked to in Issue 90, Martin Pilkington has also taken a look at AutoLayout performance and has put together some tips on how to keep your performance up when throwing hundreds of views and constraints around.
Speaking of Florian Kugler and performance, his latest article on was published this week and this time it tackles rendering performance. He builds the same table cell three times using views, layers and finally rendering directly in drawRect:. The results might be surprising if you are still going the route of drawRect: for performance.