XCode 6 features highlights

1. Single storyboard for all screen sizes iOS devices
2. Size classes for Adaptive UI, Its a nice take. With the help of size classes we can configure screen elements for multiple screen sizes
3. Preview Assistant to check output on multiple screen sizes
4. We can use Playground to check code snippets
5. Launch images can be auto generated
6. Storyboards can be used for mac apps as well
7. Asset Catalog supports more types vectors as well
8. Search enhanced
9. Designing with custom fonts made easy
10. Localisation enhanced and automated (+XLIFF Support), No need to use string files from now.
11. Pseudo localisation can be used to save localisation cost (see if it works for you)
12. Runtime localisation check support
13. Custom controls can be edited live on interface builder with the help of IBInspectable and IBDesignable
14. Debugging have feature to backtrace the blocks as well
15. Debugging and Profiling for Games enhanced
16. Support for Async Testing with XCTestExpectation
17. Performance testing with detailed information and control
18. Instruments are redesigned
19. New Profile Guided Optimisation to optimize your code for runtime performance
20. Xcode Bots to manage responsibility for bugs
21. With View Debugging feature we can inspect element on the go, #RIP Revel App
22. Debug gauges, to provide at-a-glance information about Network Activity, File Activity and iCloud usage while debugging
23. iOS Simulator got new custom screen size configurations and it allow you to keep data and configuration settings grouped together.