We had Gitlab issues for 7 years at work. It was a clear and reponsive UI, simple but powerful markdown editing. Probably only 20% of the functionality what you can theoretically do with Jira, but just more pleasant to use and we got everything done. Over the years Gitlab kept adding more features and response times slightly decreased, but still nothing compared to Jira. After changing jobs I have to use Jira and hate it every day.