- Simplified method declarations
- No semicolons on end of line
- Functions as first class citizens
- Some sort of memory management (ARC in Swift’s case)
- Implicit typing
It’s going through growing pains, as the language spec and tools are still immature. However, it’s a language with all the buzzwords and behaviors programmers currently want. Plus, if Apple follows through with it’s plan to open source Swift 2.0, a major hurdle to adapting Swift on other platforms will be removed.
As far as general non-Apple programming goes, Swift has some serious competition for mindshare in Google’s Go and Mozilla’s Rust. Go has a serious head start, and is solving real problems at Google and everywhere else these days; unfortunately, Google has a bad habit of abandoning projects. Rust looks like an absolutely amazing language, and I think it is the best-designed of the three (better type system than Go, better memory management than Swift). I’ll be curious to see if anyone actually uses it.
Swift, on the other hand, is Apple’s “language of the future.” Apple and Swift are in a similar position to Microsoft and C#. With a large development community eager to/forced to lap up whatever Apple brings down the pipe, I suspect Swift will continue to gain popularity.