I have 35 points in the shiradi tree, and yes, I use the mantle.
I have 6 points in the SD tree, mostly for the threat reduction and the DD
I have 23 Points in Dreadknought, extra action boosts and damage for the most part.
For my epic strike, I use the shriadi pin, and the Dreadknought Dire Shot. With Fusilade running, the only "special attacks" i use are Huntsend and the Dire shot. When Fusilade isn't going, I have the 2 arti AOE attacks, and Pin and the Caustic Shot.
Depending on your objectives, there are probably better ED's, but with few lives, those were the ones I chose. I have a very similar build idea but it was 12/6/2 Arti/Fighter/Rogue but it was to squishy, so 20 Arti is a much better way to build, as you can get all the ranged feats you need, and still pick up the Single Weapon Fighting line for extra HP.
I wear a simple gear set up, Wallwatch, 5PC IOD, and 4 PC Winter. This is not a min/max build, the gear set i put together in about 5 minutes, and wanted something simple. I have 2 pieces of Raid gear, the Wallwatch Helm, and the Hunting Horn trinket from Skelly Raid. Both pieces could be switched out to non raid pieces without losing much.
Artificer is in a good place, both in heroic and in end game. Its not the best ranged damage out there, but if you think about the fact that soul stones do 0's of damage, then this is a good build for low life players.