So far I am loving my eng, he does die a lot because I am speced more for damage but when he is alive he does well.
Turrets are becoming pretty useless, they have some uses but they get blown up really quick vs bosses, they can't evade and most bosses AOE will one shot them.
I am speced for power/crit chance and I use grenades mostly, IMO it does more damage than anything, underwater it destroys things, get the level 30 perk that give you a extra grenade and more distance.
In PVP i must say grenades can own, I can take out 10 people in under 30 seconds from a keep wall, if they move they are hard to hit but the AOE area is decent size.
I use a rifle now just for the extra damage over a pistol, condition damage is not all that great, I can stack 6-7 bleeds myself, now toss in 3-4 other people who can and you hit that 25 cap pretty quick and others stop stacking.
Healing.. I have tried healing, seems decent at it with the elixer gun or med kits, but I have no +healing so it could be better.
One of my fav skills so far is the elite skill that releases 2 dogs to fight for you, they don't live long but they are great for taking on a vet mob or a bunch of small mobs solo, they do pretty good AOE dmg, I took that over the Mortar because you can buy ones in PVP and honestly you won't have much use for it in PVE.
I have finished my story line quest and you get a good level 78 exotic item, so I would not spend much on the trade post on gear until you are done with your quest line.
Over all I really enjoy the engineer, my hands get a bit sore from the grenade spam, but underwater I can turn it on autocast and it destorys anything.
Hope everyone is enjoying the engineer class! No idea how our damage stacks up to other classes, but I crit for 1k pretty often with my rifle if that means anything.