Xcode 6 iPhone Simulator Application Support location
The simulator directory has been moved with Xcode 6 beta to...
~/Library/Developer/CoreSimulator
Browsing the directory to your app's Documents folder is a bit more arduous, e.g.,
~/Library/Developer/CoreSimulator/Devices/4D2D127A-7103-41B2-872B-2DB891B978A2/data/Containers/Data/Application/0323215C-2B91-47F7-BE81-EB24B4DA7339/Documents/MyApp.sqlite
I found SimulatorManager application very useful. It takes you directly to the application folder of installed simulators. I have tried with 7.1, 8.0 and 8.1 simulators.
SimulatorManager resides as an icon in the system tray and provides an option to "Launch At Login".
Note: This works only with Xcode 6 (6.1.1 in my case) and above.
Hope that helps!