Now that my mage is 80 and ive had some hands on experience with Sunfury.
I must say, the machine gun playstyle with unleahed inferno and hyperthermia. Means you get back to back pyroblasts and the burden of power talent gives you a fireblast that unleashes 4 meteorites (i remember it was 8 in alpha 
)
Im getting two to three combustions in a boss fight.
All in all Sunfury is so freakin fun. I love my fire mage.