Aside from the extra load (and long requests, which is a bigger factor for non-async app servers), you need to take into account the physical location of your a

Aside from the extra load (and long requests, which is a bigger factor for non-async app servers), you need to take into account the physical location of your app servers. Depending on where the user is, there can be drastic differences in performance uploading to, say, us-east-1 vs ap-southeast-1. With S3, you can enable transfer acceleration so that the user uploads to whichever is their nearest region and then AWS handles it from there. This can give huge speedups.