Basati uses Chatter daily and we love it!

All departments are using Chatter. We use it as our form of communication for all client discussions. It is meeting our business needs very well as it allows us to find all communications on an account in one place in Salesforce so we don't have to sift through multiple emails. All features seem to be done well, but I think if we could post multiple photos or screen shots under one post that would be helpful.