Its almost like your replying to my other comment, in the last blood pact, but here!

Typically when I first started running heroics, I would normally put down a teleport always, granted I was usually waiting on the healer to drink at the time (yay first week heroics OH GOD OH GOD). When questing? Almost always as well... but thats probably a side effect of leveling on a pvp server.Soloing old world stuff? Not quite as much.

Regarding Fel/Demon armor and soul link.
Druids do in fact (I didn't know about the 15% mitigation previous to this >.>) burst damage prevention. Which actually fits better with this tier of content. Some encounters (oh hai thar H-Chim, I'll be seeing you soon) not so, others (oh hai thar normal Chim) support burst mitigation. I suspect this will fade in later tiers as we move from burst AE to sustained AE "aura" encounters.

As destruction and demonology, there are times where you may want to switch, however as affliction I doubt this. The DPS trade of is similar to just casting drain life as your filler for a few seconds, and the effect will be similar, but you won't lose 2 GCDs switch from and back to fel armor.