The main thing to know about Swift performance is that it varies hugely depending on what you're trying to do. I think it will take some time for the implementa

The main thing to know about Swift performance is that it varies hugely depending on what you're trying to do. I think it will take some time for the implementation to mature to a point where it becomes less hit and miss performance-wise. Swift as a language has all it takes to create a consistently fast implementation. The wildcard is probably the decision to go with reference counting over a tracing GC. We'll see how that works out. There are good arguments on either side.