I really liked basecamp in earlier versions when it was more about project management, but as they evolved into a product servicing 'teams' I felt they really lost a lot of their core functionality.

These days I can't really get excited by it - if you've got Slack and a team dropbox, you're covering most of the functionality listed above. Not to mention that Slack and Dropbox are free for most purposes that a small team requires of them. Slack, in particular has a ton of integrations with a ton of different SAAS products that would negate the need for something like basecamp.

Throw in something Like Trello and Asana, which are way more polished than Basecamp, and you've got a winner team stack.