There have been others who complained of similar behavior but no one was able to prove where the slowness was being introduced. My tests are that I can saturate my 100Megabit connection with a single download from Google Drive on a linux host.
HS -> rclone copy robgs:/cams/backyard/20170619/01_20170619232717000.MP4 ~/ -v --stats 15s
2017/06/20 13:09:15 INFO : Local file system at /home/robert: Modify window is 1ms
2017/06/20 13:09:15 INFO : Local file system at /home/robert: Waiting for checks to finish
2017/06/20 13:09:15 INFO : Local file system at /home/robert: Waiting for transfers to finish
2017/06/20 13:09:30 INFO :
Transferred: 174.996 MBytes (10.632 MBytes/s)
Errors: 0
Checks: 0
Transferred: 0
Elapsed time: 16.4s
Transferring:
How are you testing the speed for the mount? I hope you are not looking at the stats on the mount itself as those r clone stats are averages over the life of the mount.