I've been using a Copy account... or rather not, as it's not happy behind the company's firewall. Did discuss with their devs, but they weren't overly worried about fixing.
Cubby, OTOH, works perfectly for me at work and I use it all the time, but not for a lot of stuff.
SpiderOak's new version got more DropBox like, and I've used SO's rooms for 'sending' documents to printers and the like (the way SO's storage works you can have as many copies as you like without it adding up to your allocated space).
I liked the Copy icon