Regarding pug groups. EC is probally some of the better exp i get with my gimp monk tanking. It's prety easy to just mass pull there and keep the mobs flowing. The biggest thing about it though is with mediocre geared dps you can still clear all the orcs and have to sit for respawns. After orcs are dead you can go kill giants, whirlwinding mobs or yetis... the latter two are annoying to fight with pug melee dps, which is a dime a dozen. Giants tend to not be worth the time as they are big mana drains for an exp group.
FG is a prety rewarding zone if you just want to grind, lots of mobs and ok trash loot. There's one big thing that i dislike about FG, the fact that almost anyone that goes there always wants to do LL for a chance at the token. It's also kind of annoying to drag people around the zone who don't know their way.
For a more rewarding time, mostly with people i know, I like going to FR the most. The fact that named have a chance to pop as you kill trash is just so attractive to me. There's also a ton of named throughout the whole zone and killing any of them (aside from ghosts imo) is always worth it. To me FR never gets old /shrug
Elds actually has a 45 minute respawn and really is no good for a geared group. However, I can get nice pp/xp just duoing it that it's often a better alternative than to pug. I find it gets pretty boring here too since like everyone has done it since they have been 60+

. Not a bad zone to start with, but it gets old.
I've only done a little emberflow, it seemed intimidating at first. The more I go there the more I like it. Definitely wouldn't recommend trying this if you think elds is one of the better zones out there. But if you make it to the point where it's not just a crawl and get to see some of the named, it's a rewarding zone.