Bugs in the S4?

While I'm sure there were a few bugs considering all of the custom software Samsung is putting into the Galaxy line I doubt that is the sole reason for the 'delay'. Let's not forget that the Galaxy S3 released only 10 months ago. To double the phone's performance and add as many features as they have in such a short amount of time is incredible. Plus, the 600 cpu processor is just now ready for shipping. If anything caused a delay I believe it was Samsung having to wait for the cpu to hit mass production levels.