Nice thing about it is that it supports custom fields.
So for most of your fields you can just add them. (It has some default templates, but I ended up starting from blank.)
Notes can be added with the comment sidebar.
How to Demo is a bit awkward. To my knowledge it only supports one Rich Text Field. (Which takes html, with a wysiwyg interface) per card.
You could use the rich text field for this and for your extended description, (since it has HTML you could break it up how you like).
Its other big features is its querying so for example I could do a query to find me all cards that has been in testing for more than 5 days.
It has some fairly good charting, with a bit of work I got it to show a burn down chart, that excludes all cards that were prioritised as Don't Care.
Its workflow management is pretty good, though a thing that caught us out was you can't drag and drop a card from one area to the next to trigger a work-flow action. (Eg we had a action program that would Automatically Set a field to say which date it entered testing. This feild would be set if you clicked "move to Testing" but not if you dragged and dropped.)
its super configure-ability is really great.
I manipulated it to be the bug tracker.
I put together a Tech Debt Wall (with Pain caused vs Pain to Fix)
Learning Time: I would estimate it took me about 16 hours to become fully proficient in it, and about 4 hours before I could have enough understanding an d enough to create/setup a project to explain it to my team. Once i did have that done it took under an hour to explain it to everyone else.
Cost: It is Free for up to 5 users, and about $250/year for more.
You access it through your web-browser,
you can either host the server yourself (I did) or Thoughtworks can host it for you. This may not be true any more, I can't find much about hosting it yourself on the website.