What are the fresh Bitrix24 alternatives for task management?

Question

Task Management

Hello!
Please advise a more or less suitable alternative to Bitrix24, based on the following requirements:

1. Grouping by projects
   
2. Hierarchy of tasks - the ability to set subtasks
   
3. Task Comments
   
4. Flexible setting of task fields, or the presence of these fields: Created, Title, Description, Assigner, Performer, Observers, Tags, Deadline, Priority, Status
   
5. Gantt Chart
   
6. Specifying the task director (initiator) without creating an account for it (for example, through a label or a special list of possible directors)
   
7. Reports or a convenient filter
   

Also desirable , but not critical:

1. Simplicity, ease and intuitiveness of the interface
   
2. Notifications by email/sms
   
3. Planning in calendar and working day
   
4. Collaborate on tasks and documents
   
5. General chat
   
6. Installation on your server
   
7. Free or reasonably priced for up to 30 users
   

Were tried, but did not fit the requirements:
bitrix24.ru, megaplan.ru, asana.com, producteev.com, trello.com, planfix.ru, redmine, teamlab.ru, yammer.com, projectorcrm.ru
Most of all, of course , Bitrix24 is suitable, it is fancy, but not very flexible. And to create tasks in it according to your requirements, you have to repeat unnecessary actions and be distracted by unnecessary things.
I would like to know about the alternatives that currently exist, both powerful and simple.

Answer 1

Thank you all for your help. I settled on Trello.com .
For myself, I made the following conclusions:
1) If the head / team has fresh and creative brains (and the team is not bloated), then Trello is the best. This is freshness, freedom, visibility, simplicity - hence the energy to work (This is flexible Kanban). And also it is communication, notifications, calendar and subtasks/checklists. Of the minuses - only the lack of the usual control over the execution time (but there are solutions through the reportsfortrello.com API ), and the lack of a boxed version.
2) If you need a classic approach with flexible field settings, then definitely YourTrack from JetBrains (thanks to Evgeny Popov!) It is very reminiscent of AtlassianJira and looks like a fresher solution than Redmine with its bunch of plugins. Review here habrahabr.ru/company/JetBrains/blog/239385

Answer 2

I am using Pyrus . On points that is:
Basic requirements:
1. Yes.
2. Yes.
3. Yes.
4. Yes.
5. No, but it is not necessary if the rest is available.
6. Yes.
7. Yes.
According to the desired requirements, everything is also there, including the free version. In addition, a very important advantage is the ability not only to manage tasks, but also to create and launch business processes using a visual editor, which I use regularly. Cons: boxed version only in the most expensive package.