Recent versions of acd_cli have largely fixed all the issues I've had in the past. I've found that essentially all issues can be solved by not writing directly to the cloud drive, but using a unionfs and uploading on a cron job.

There is no 2gb limit that I have run into. I just checked and I have several >30GB videos uploaded to my cloud drive, so I can safely say there is no issue there.

Edit: For some completeness, here's how I have everything mounted and syncing.

  acdcli mount /mnt/amazon_real --interval 30000000 -ao --uid 112 --gid 118

  unionfs-fuse -o cow /mnt/cache=RW:/mnt/amazon_real=RO /mnt/amazon -o allow_other

  0 * * * * acdcli upload --remove-source-files /mnt/cache/* /TV/ --max-connections 10; acdcli sync

And that's it. The last one is a cronjob that runs every hour, if that wasn't obvious.