In case anyone was wondering the functionality differences between #JoomlaK2 Tags vs. Categories, I have created a little list:

Ordering - Categories: Yes | Tags: No
Nesting - Categories: Yes | Tags: No
Description & Image - Categories: Yes | Tags: No
List Display Settings - Categories: Category Specific | Tags: Global

Feel free to comment if you have any additional thoughts or suggestions.

Nice...

For K2 Tools display, would be nice if we can have a dropdown select for tag ;)

@Diego I believe that feature will be introduced in K2 2.7
www.joomlaworks.net/forum/k2-en/44083-what-k2-tags-limitations#149004

Just to clarify, the tag filtering will be included in K2 content module, not the K2 Tools module.