I signed up during a 25GB free deal they had a while a go. I use it along side Dropbox and Google Drive and as far as I can tell it's as good as either of those.
Have you tried downloading back your files? Is it as seamless as Dropbox?
The other day I signed up with SpiderOak (over the recent buzz about security and all) and luckily I had to share a folder with a friend in another country. He has the fastest bandwidth available but complained that his connection would drop during the downloads out of SpiderOak. I switched the content to Dropbox and he downloaded trouble free in one go.
