Any MM with /dark is good, and it gets its best powers at the start even 
I have no experience from mercs though.
I know /dark is good, just didn't expect Mercs to be so damaging. Never hear any good publicity about them. Have tried all the primaries and /Dark and whilst Necro still remains my favourite for the control factor, Mercs is a fast killer
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
Mercs imho at higher lvl are way too much DoT based. You see 2-2-2-2, 3-3-3-3 popping up, only except the seals sniper shots and commando's slug shot. At that moment it becomes really annoying, if a mob is only left with 20hp and 1 merc starts his 5x4 DoT dmg, by the time the health reach 5, all your other mercs start their attack also.
But they are somewhat more mezish based, specialy the seals got teargas and flashgrenade, very nice to have
And serum.. well thats for now a plain waste of power slot.
50)Sinergy X/(50)Mika.
(50)MaceX/(50)Encore
Sign the petition, dont let CoH go down! SIGN!
Oddly dont have that planned in my build, from all the descriptions I've heard
I like DoT, but yeah can be annoying when everyone DoTs the same dying guy
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
I love playing my ninjas/dark MM, mostly solo though as I hate large mobs on MMs. Pets die far too fast with large mobs around 
so I mostly play in teams 1-3 people.
I love ninjas, they got some holds, caltrops, immobilize and all around nice damage. /dark is pure love aswell, great -acc, cone fear, holds, heal, tar patch; everything to keep you and your pets alive and giving the enemies a hell to get you down 
- @DSorrow - alts on Union and Freedom mostly -
Currently playing as Castigation on Freedom
My Katana/Inv Guide
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. -Einstein
Mercenaries *are* good, but I think are the least talked-about MM primary. The reason for that is probably that they're generalists. A few buffs, some debuffs, some control, moderate damage - the other sets do all of these things better, but no other set does all of them.
Mercs' damage type (lethal) does of course start to get resisted more as you progress, but the Commando gets Flamethrower which helps.
They're fun all the way, though.
Thats what i thought at first too, they're fun. But getting close to 40 and seeing fellow pets going (specialy thugs) i sometimes get pretty dissapointed looking at them. Commando often uses his full auto and LRM when there's only 1 mob left close to dying. And the early mentioned DoT-ing dying mobs.
Kinda like the more you rely on them, the harder they become. Best scenary having full debuff running (TA here) and see all 1st pets and commando open Full Auto.
Their main strength imho is their range, its slightly further then the other pets. And since they are 100% ranged its great to have them as /dark or /TA. Sure once in a while a pet decide to go melee range, but just call em back and its basicly nonstop ranged fighting.
Main question remains, why the <bleep> do the seals have stealth.. you cant use it since they (de)activate it totaly randomly.
My tip though, try to avoid the final upgrade on your medic. Although you miss the mez-resist from it, your medic really getting close to no healing at all once he has the mez-power. But as /dark that is a lesser problem then a /TA :P
50)Sinergy X/(50)Mika.
(50)MaceX/(50)Encore
Sign the petition, dont let CoH go down! SIGN!
Cheers, a fair way away from the medic at the moment.
It feels very different from my Necro/Dark. My Merc/dark adds damage to teams and fits in well, when I team with my Necro/Dark I wonder why all these people are holding me back. The Mercs have less survivability so I have to work as a team, but more offense so I gain more from it.
Am a bit disapointed in my T2 pet at the moment, but the second upgrade on it looks good. Take into account when my necro had the second pet first upgrade gave disembowl am not seeing anythin simular from the seal.
I want to see how the fear works with them am imagining I will get more out of it, especially when I get my AoEs. The necro pets tend to melee and lose their AoEs on locked down mobs
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
Does it keep going from Strength to Strength?
I must admit mine is only level 9 right now, but damn I feel tough. Its not my first MM, and its obviously not my first Dark but those orange numbers make me smile. I do miss the Melee of my Necro, but the constant stream of DoT seems to make up for it. Control down, upfront damage up.
Anyway just wondering what peoples experiences are of these powers combined.
I'm also mucking around with a Ninja/Poison. Its my 4th attempt at Ninja, and the last secondry so I hope that works out too.
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"