In full 810 gear with maxed out 750 weapon, the 7 DPS specs I tried all pull between 100k and 110k DPS {Without using their 3 minute major CD. No Avenging Wrath, No Metamorphisis, etc}. That seems to be the standard for that level of gear. Some classes may pull away from that and some classes may not have proper gear to scale their stats, but I digress. From someone just trying to decide what class to play: They all seem viable.
The best DPS in your raid, assuming skill is equal, WILL be the person with the most worked-on weapon. Spriest is a bit of a conundrum, though. They might end up blowing everyone out of the water thanks to their suicidal talent. TWO minutes of apeshit worries me...
Havoc seems perfectly fine with three spec options that *should* be good in various situations. Diverse rotations that excel in different areas is always good for a well balanced class. Need high mobility? AoE? High damage on one target and strong AoE otherwise? Flat out aoe? etc. They bring a lot to the table.