Xcode 6 introduced a new localization workflow which uses the open .XLIFF format. Xcode extracts the strings from NSLocalizedString, strings in storyboards / XIB files and creates a single XLIFF file for each localization.
I'm looking for good localization tools that translators can use to open and edit the files exported by Xcode.
The translated file needs to be saved as .XLIFF and then imported into Xcode. Xcode creates a new localization for the target language specified in the XLIFF file or updates the existing localization.
Which localization tool(s) do you recommend?