128kbps MP3 delivers noticeably higher audio quality, retaining more of the original recording's dynamic range and detail when compared to 64kbps AAC+. However, the 128kbps MP3 file will be roughly 50% larger than its 64kbps AAC+ counterpart - doubling the storage requirements and increasing transmission times.

For on-demand audio content or podcasts with long-form storytelling, the file size difference between 128kbps MP3 and 64kbps AAC+ might not be a major concern - though it should still be taken into consideration when determining bandwidth and storage limitations.

For live or real-time broadcasts, the difference between these formats becomes more critical. A smaller 64kbps AAC+ file size allows for faster encoding and transmission, making it more suitable for applications where latency can't be tolerated – think live sports or high-stakes remote broadcasts.