This looks like an exciting new product to give a try. It's beta right now, which means free, and if it works as advertised it may become the handiest Xcode tool on your Mac. I like how you can edit labels and jump straight to the view code from the simulator. That's cool!
Edit views and layout constraints in real time, simulate running on other devices, and jump straight to the source code, all from your Simulator - zero configuration required.
Sherlock for iOS by InspiredCode