Whilst they do mention they have various levels of strong encryption, they also mention (in the privacy policy under "Collection and Storage and Use of Private Data Files") data deduplication, which indicates they still have visibility and could be served with an NSL or FISA order.
(Not plugging or anything, dropbox would have done the exact same thing if I had the space for it)
For the application itself, pretty much identical to dropbox I believe. I haven't really used it since I uploaded.
I'd be an active Google Drive user, however the app kept crashing on my macbook, so I had to give up. I even spent a few days troubleshooting it with Google support to no avail.
So long as the copy.com program doesn't crash on me, this will be my online storage of choice for the foreseeable future.
Also, I did a google search to see if Copy had been announced on HN yet, and it hadn't, so I felt that while I was going to prosper from providing the info, I was also contributing more signal than noise to the HN community.