Last night we ran a regular heroic, then decided to give the new heroics a go with our group. Our DPS is lower than the average pug, but we have people who are generally pretty good at
1) Not standing in bad
2) Interrupting bad
3) Using CC when it is needed
We go into the instance, and the first Echo we get is Tyrande. We clear all of the trash with no problem. We get to Tyrande and get her down quite a bit before we wipe. I believe we took her down on the next attempt....with just our ret paladin still standing. Keep in mind that for two of us, this was the first time in the instance, and one was in there healing for the first time.
Next up we got Echo of Baine. I think that it took us three tries to take him down, and at least two of the tries, we had very unlucky experiences with the totems ending up in the lava.
We had a bit of trouble of Murond, but took him down on the third or 4th try....which was not that bad considering that on the first attempt we ran out of hour glasses and only got him half dead.
My wife on her Boomkin ended up on hour glass duty. Unfortunately, she did not get to spend much time DPSing as she was too busy dodging yellow crap. For some reason it gravitated to her. Melee barely had to move. She was running for her life all night.
Overall, I was very happy with completing it. I also thing that the first instance is the hardest of the three, so we are looking forward to the next two.