I've been a happy AeroFS user at a couple of companies now, and always recommend it to anyone with a group of people sharing files which are at all sensitive.
Other systems like Dropbox are fine for photos or public content to share with people quickly (since it's pretty widely used), but within an organization, or whenever you have security needs (audit trail, meaningful encryption, firewalling, etc.), AeroFS is the easiest choice. (running your own fileservers is the alternative, but outside of an all-Microsoft world, that's actually pretty hard to do well today.)
Other systems like Dropbox are fine for photos or public content to share with people quickly (since it's pretty widely used), but within an organization, or whenever you have security needs (audit trail, meaningful encryption, firewalling, etc.), AeroFS is the easiest choice. (running your own fileservers is the alternative, but outside of an all-Microsoft world, that's actually pretty hard to do well today.)