People may wonder if guilds are getting the achievements this quickly because Ulduar is too easy. My opinion on the matter is that Ulduar itself sans hard modes won't be abnormally challenging, however when you put in the hard modes and various twists to the encounter in order to earn the achievements, Ulduar is going to become quite challenging.
The achievements that have made the list so far, like A Quick Shave where you have to kill Razorscale with her only flying into the air once, just requires a lot of DPS. That's not too hard for most geared out groups to muster.
Take a look after the break for GuildOx's list of the top five Ulduar 10 and 25 man achievements, and head over there to take a look at things overall.
Top 25-Man Achievements
Heroic: Shutout – 1.89% achievement rate
Heroic: A Quick Shave – 1.27% achievement rate
Heroic: Nerf Gravity Bombs – 0.88% achievement rate
Heroic: I choose You, Stormcaller Brundir – 0.48% achievement rate
Heroic: Nerf Engineering – 0.27% achievement rate
Top 10-Man Achievements
Shutout – 2.81% achievement rate
A Quick Shave – 1.31% achievement rate
Nerf Gravity Bombs – 0.63% achievement rate
Nerf Engineering – 0.51% achievement rate
Orbital Bombardment – 0.39% achievement rate
Patch 3.1 is live and it takes us into Ulduar, delivers us dual specs, and brings significant changes to all the classes! We've got you covered from top to bottom with our Guide to Patch 3.1 and the official patch notes!