Belinda, I can honestly answer yes to all three questions.
1. Darkbirdy's UI is amazing, but like all (including me) he made SMALL mistakes. I have changed these. The encumberance issue I talked about in the readme, and also I have fixed a few of his colors that were off (like in the repair menu, the players gold showed up as yellow, not the usual yellow/tan)
2. Oh yes, extensive changes. Mainly cosmetic, but also many bugfixes.
Look at the bugfixes near bottom of first postAnd those are just the bugfixes for 1.1, for the complete rerelease of 1.0, he dynamically made everything easier to modify, bugfixed, and aesthetically made everything better.
3. Oh, my modification is special, if not magical.

Yes, there are some minor bugs and things I have personnaly fixed, like it says in the revision history, I have fixed some bugs that have been bothering me since I started using DarkUI (The inventory bar issue), and i really worked to make this UI perfect (still am working). Also my mod is an all in one package of many mods that it took me months to figure out existed.
"This package includes the whole of Darn's UI version 1.1, and all of DarkUI version 2.40. It also contains Darkbirdy's DarkUI Loading Screens, and the Shivering Isles DarkUI Loading Screens by HTF. It also includes a DarkUI-ified Menu Loading Screen and Map-Scroll Video by Fritzdog. This also fixes tiling issues with the textures in the map and inventory screens, as thanks to the amazing work of Brumbek."
There are some minor issues with Brumbek's texture fixes, but he's fixing them as we speak, and another bugfix release will come as soon as my computer is sent to me.
Thanks,
Dylan
Oh, and Offkorn, if you're foolish (like I was) and don't know that BSA edits can make it so you can't uninstall, and you don't know that you can remove those BSA edits with the push of a button, than it can cause you problems, like it did for me.