It is not to tell which one is the best. because which one is good to tell based on team requirement.
if your team have single developer its good for storyboard working less consumption time.either more number of developers use xib because it is not easily to merging the module/tasks
[xcode-using-storyboards-and-xibs-versus-creating-views-programmatically][1]
#Using XIBs
Advantages: