at 15k haste (roughly) a heroic thunderforged spark gets really strong, you'll 90% of the time see it go above 3 stacks on pull (I most of the time get it to 5 and in some cases 5stacks for over a minute) which is a huge gain over spark. Spark isn't "bad" but it has a huge ramp up time which means if it doesn't proc on pull (which is when you have pot, cds and feather line up) and when it procs it can proc when you have nothing at all ready for it, iirc when I used spark it had roughly 1min 10sec ramp up time which ment it would line up with the second avening wrath if I was patient enough to wait for it. With Feather though I'd much rather wait for that to proc and use wings with that since it's better, the reason PToR is considered better is because it's a consistant boost, think of it like a beasted up wep enchant. It's just always up, even if it's "only" 1-2 stacks.
Most recent Tortos 25hc kill:
http://worldoflogs.com/reports/rt-fb...?s=1207&e=1564
356sec kill time.
225sec uptime on "rampage", PToR proc. 63% uptime.