Ranked in these QuestionsQuestion Ranking
Pro Can be used as a Just-In-Time language
Pro Modern syntax
Pro Inherent parallelism
Pro Low memory footprint due to reference counting
Pro Backed by Apple
Pro Works with Apple's Cocoa and Cocoa Touch frameworks
Pro Performance speed comparable to native C
Pro Swift has some clever tricks up its sleeve
Due to having elements of a functional programming language. Things like 'map' and 'filter' for example.
Pro Uses LLVM compiler and Obj-C runtime allowing C, Objective-C, Objective-C++ and Swift code to run side by side within a single program
Con Swift is a moving target
They've released 1.2 so far, and 2.0 is coming soon. Every small update brings adjustments to paradigms (such as how to do type casting) that can be a little frustrating to absorb. Objective C was also constantly updating, however, but not at the same rate these days.