Originally Posted by
Derpsmash
It kind of depends on your gear, but overall destruction is the best performer. In lower gear it is miles ahead of affliction and demonology, but the gap closes in once your mastery and haste levels go up and fights become shorter. Affliction will still outperform destruction on fights involving heavy multi-dotting, and once in appropriate gear, also on fights that are short - this due to afflictions strong burst.
For soloing you'll want to go destruction with soul link, soul leech, grimoire of supremacy and the voidlord. It's not as strong as it was pre-5.4, but it's still very viable for soloing a lot of content, up to and including Dragon Soul for the better geared players.