transparency - Photoshop: How to make background transparent without affecting image quality?

I'm really new to Photoshop, but I use Indesign and Illustrator regularly. I have a picture of a product (books basically) that have a white background and I need that background to be transparent. I used the quick selection tool to select all the white space, then selected the inverse, cut and paste into a new file with a transparent background. When I do this the image ends up looking different-- kinda grainy, ragged edges. What is the best way to change the background to transparent without losing the image quality?

Here are links to the photos

Original:

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After trying to remove background:

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