Updated the spreadsheet with some new data points (and some tidy ups since now external).
Overall Speed Results
Onedrive/Google still the champ - solid averages with no outliers
pCloud still strong but with a couple of (not so bad) outliers.
Backblaze is good but there was one major outlier (more on that below)
Box over Webdav looking pretty good (but over a slightly lower sample size since started later)
I examine averages as well as variability of the backup time. Jotta is a fail (and likely to be dropped from test suite soon) since there is so many outliers.
For one particular run with Box over Webdav I was actually watching the status bar and the outlier for Box (which has been otherwise very good and consistent) was due to operation ‘compacting data’ (and post verification). Not sure what happens in that operation but it sure is very costly and maybe worth devs to look into how to optimize the transfers to reduce the impact.
Obviously the best result is local storage which is much better than all cloud providers. One particular feature of pCloud is to give a virtual drive which may give best of both worlds (speed of local but then later sync to cloud safety and without the cost of local storage space).
Need more research since the pCloud virtual drive is (transparently) cached and so does consume some local storage but assuming that pcloud cache strategy is sound then then the impact to speed may not be high but otherwise invisible to user for managing local storage. Will update that in next round.