GDR means General Distribution Release. They are released to the public on Windows Update and other places.
LDR/QFE updates ( Limited Distribution Release and Quick Fix Engineering ) are on another "branch" of development, and sometimes have to be requested. They usually are created to fix specific problems.
Think of it as "testing": you have the latest fixes, but also potentially new bugs or regressions.
When fixes of LDR/QFE are considered stable, they are merged in GDR branch. (the "stable" version )
The KB posted on Windows Update contains the two branches, so once you have installed LDR/QFE hotfixes, you're staying on this branch. (until the next service pack or if you uninstall any updates on LDR/QFE branch).
As far as which branch to use, it's really a matter of personal preference. Some prefer the GDR branch as there are fewer updates to integrate and they are slightly more stable, though they are not immune to issues. Others figure that all of the LDR/QFE updates will eventually be rolled into the GDR branch anyway, or the next SP if there ever is one, so you might as well be prepared. While there is a very small risk that new bugs are introduced, the cases where that has occurred are rare and they are usually corrected quickly with yet another update. LOL I personally have not run into a problem using the LDR/QFE branch.
Cheers and Regards
This post has been edited by bphlpt: 24 February 2013 - 04:16 AM