NOOB 5D Mark III Question from a D800 (owner/switcher???)

Personally I disable ALO and HTP (highlight tone priority). I would rather make such adjustments in my exposure settings myself and in post processing rather than relying on the camera to change my settings/processing for me. You may find the following an interesting read:

http://shootintheshot.joshsilfen.com/2010/11/29/highlight-tone-priority-in-canons-dslrs/

By the way, I think ALO only effects JPEGS anyway. I think the ALO is ignored for RAW.

Hope someone else comes along to validate the above. Welcome to the dark side