Nero recode faster then encode from original file source???

Does Nero Recode transfer title or track faster then video encode file
from originally source file?

I am trying to put my videos on a dvd+r.
Is it that I save time more by using Nero Recode from a pre-recorded dvd which
I originally made using source mpg and avi files. Using source file takes
ages to encode video to burn on dvd+r more so then Nero recode, right?
So I choose the tracks I want from a particular DVD+r.
So I put many video tracks from different dvds, taking one out (DVD) and
putting another in to re-code the ones I like?? It will still work.
Do I save it as an image then trnasfer it to DVD+r
In the end does it erase the temporary image or what?

Anways irregardless of what method I use, the quality of the video would be
the same right? If I don't change any of the settings, right?

I am new to Nero Recode, wonder if it is worth while to use????

Thanks

Bun Mui