So I was holy til 62 and decided try out disc spec because of the very attractive abilities. So I re'specd and of course, had a fun *** time. So since then I've still healed for groups and was very successful. However at 64 I healed a group for sethekk halls and did fine til the first boss. We wiped a few times and as healer I took responsibility even though the tank couldn't hold aggro worth a damn and there was no CC whatsoever.
Now I plan on staying disc spec'd for good, but I love healing groups. So far as long as I have a decent group I heal just fine (not to mention I never run out of mana). However will Disc spec with good gear cut it when it comes to healing groups for heriocs or other level 70 instances?