It's nice, has most of Jira features that were important for my org. Philosophy is bit different in some parts (eg. backlog management), so there was some complaining, but overall it's ok.

Only one major complaint: For main license, you can buy and own license for selfhosted version. However for helpdesk addon it's subscription only, which sucks a lot. For Spaces they have only subscription-based pricing, even when self-hosted. I hope they don't go Atlassian way.