Yep, dropped Dropbox for SpiderOak ages ago due to a number of really poor security failings on Dropbox's part. (Remember the day they accidentally allowed blank passwords to login to anyones account?)
Dropbox is probably the LEAST feature-rich and mid-range to high in the cost part , compared to all the other file sharing services out there.
edit: http://www.geek.com/news/dropbox-security-glitch-meant-any-p...