1399-1899. 95%+ of vanilla is improved. Whole world changes with a dynamic, non-deterministic structure. more than 4 years of development with the same Mod founder (Darken). Historical starts, Truth in history, Optional cheats, Nation creation aids/improvements, Rebellion Improvements (makes much more sense and plausibility), More Nations, Vanilla Fixes and improvements, Extensive Game Balancing, New events, New Graphics, New religions, New Trade Goods, Custom in-game settings, Improved dynamic EU3 feeling, New provinces, less wasteland, Complete MP or SP compatibility, 100% vanilla events improved, New missions, New decisions, New Spy missions, Overhauled Navy, Less Annoyance, Much Better AI, More difficulty levels, Idea tech slider, Includes other mods, Vast amounts of cross referencing between events, missions, and decisions. This list could go on for a long time.
This is what the menubar and topbar now look like in TN 11.84 for HT which I think will be released on 12.15.09 (europe time).