I have worked extensively with both Swift and Go. The currently available Swift implementation in Xcode is fairly closely tied to Cocoa (and hence OS X); I think this would be a serious barrier to generic server-side usage of Swift, so I'm curious to see if they have done anything about that (and what).
Otherwise, it's a fairly decent language. It doesn't have Go's concurrency baked in to the language, but on OS X you can use Grand Central Dispatch (libdispatch) which is a very decent concurrency library and it works very well with Swift, I'm hoping it will be available in the Linux port of Swift as well.
Besides the more sophisticated type system, a major advantage (or disadvantage, depending on how you look at it) of Swift over Go is it's memory management mechanism: it uses Automatic Reference Counting, which makes garbage collection more deterministic and efficient, at the expense of a certain level of overhead in the developer's thought process (e.g. the developer has to be mindful of things such as reference cycles etc).
It's not ready for production in this release according to the site but libdispatch and Foundation are both being ported which should speed up server side development on Linux.
Otherwise, it's a fairly decent language. It doesn't have Go's concurrency baked in to the language, but on OS X you can use Grand Central Dispatch (libdispatch) which is a very decent concurrency library and it works very well with Swift, I'm hoping it will be available in the Linux port of Swift as well.
Besides the more sophisticated type system, a major advantage (or disadvantage, depending on how you look at it) of Swift over Go is it's memory management mechanism: it uses Automatic Reference Counting, which makes garbage collection more deterministic and efficient, at the expense of a certain level of overhead in the developer's thought process (e.g. the developer has to be mindful of things such as reference cycles etc).