EB has slightly higher DPS, but complicates your rotation and makes it harder to move. I use PE on every fight and I rank on tons of fights, normal and heroic. It's not a large enough difference to worry about, and it really is a nice quality of life bonus.
Stupid question but you just let the elemental attack right or do you use it for the 5% buff? I was thinking about trying PE out. Also do I use the glyph as well?
I believe you should always have the elemental attack unless it cant hit the target or you somehow can do about 800k dps or sum rediculous number like that. Cant remember where I heard that number from and may be off a bit but you need to do unreachable dps to get more dps by channeling the ele. The glyph depends entirely on the fight and your raid dps. If you get a third use out of it with the glyph but only 2 uses without then it might be a slight dps increase for instance.