I wouldn’t recommend Stripe. It offers the least value. There are a lot of bugs and problems in it for things that should be really basic. With payments, there is no room for error.
We use Zendesk for our customer service center since it is real time chat for customer support. Some people are using it to manage a “customer support inbox” but we use them to power our help center.
Our marketing team uses Trello to track their stories. They don’t need something as advanced as Pivotal Tracker.
We use Pivotal Tracker to prioritize engineering stories like bugs and features. We do bug reporting, quality assurance and other stories in Pivotal Tracker. Pivotal Tracker is expensive, but the engineering team needed something more advanced than Trello.