There's not a lot of new complaints or answers in here -- lots of it has already been discussed on the forums and in our own posts. But Slashhug does a great job of wrapping it all up into one big tasty dual spec sandwich, so you can catch up on all the thinking about dual specs so far. The bottom line, in terms of player reaction, is that dual specs will allow you to do more with your class than you can with just one spec. If you want to heal, you can still heal, or if you're built for tanking, you can still do that. But in groups where things don't quite fit (you've got a few tanks and your DPS is a little low, or your Priest could use a little extra help healing for this boss fight), dual specs will let you make the necessary tweaks right then and there, and excel that much more.
Patch 3.1 brings us Ulduar, dual specs, significant changes to all the classes, and more! We've got you covered from top to bottom with our Guide to Patch 3.1.