Should I turn off the Shutterfly VividPics autoenhance feature?

Yes

Shutterfly features VividPics technology which automatically enhances and is applied by default to all Shutterfly prints. However, if you have edited your photos in UpShot, you will want to turn off this feature as a second enhancement will likely produce a poor result.

To turn VividPics off, sign in to your account and click the 'View & enhance' tab, select the picture(s) and then click the link on the right of the picture views "Enhance/fix pictures" and it will bring you to the Enhance section. There, click on the green 'Effects' tab on the right. On the lower left side of the screen, check the box marked "Do not apply any automatic corrections to my picture." If you have several selected pictures, click on the link "Apply this effect to other pictures". Then on the next screen click "Next" in the upper right of the screen to apply effect and a processing window will appear to show you that this has been done.