For anyone interested, the SpiderOak One unlimited account (which they said would never happen again) is back for a week. Of course it costs $30/year more than last time, so I guess it's not technically the same offer.
https://spideroak.com/aug18unlimited/If you consider this, please keep in mind that unlimited space means lots of space subject to certain restrictions, see
here.
(Disclaimer: I am using an unlimited account from last time they had this offer, and am quite happy with it.)