On 10 man this fight is quite a faceroll right now. You can go with 3 healers, one full focus on dispelling and still not have any trouble dps wise. The buff will run out around 10 %, BL the rest and its done.
On 25 man the last time ive done it is months ago, in t11 gear. The fight wasnt so hard but just very unforgiving, so I dont think it can be outgeared on 25 man as much as on 10 man.