What is Visual Studio GDR R2, and do I still need the Power Tools?

Question

I am working on quite a large DB based project and I like the look of a few of the power tools.

Looking through the related downloads, I found out about GDR R2, I cannot find out that much information about it - Not even sure what GDR stands for, but one thing that caught my eye -

"this release incorporates many previously released Power Tools as well as several new features"

It also says under the install section -

"Uninstall the Database Edition Power Tools if installed."

So,

1. Does it contain all of them and a few extra features, or only a few?
2. What does GDR stand for!?
3. Is it worth using it over the standard power tools?

Edit -

Paul Baker's answer is great and has answered 2, along with giving me a lot of information, but I am still unclear on points 1 and 2. Does anyone know?

Answer 1

GDR = General Distribution Release.

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