All scrapper primaries are nice, but personally I think dark melee is bit weak.
For matrix style, naturally Martial arts. When you get eagles claw, its very matrix like 
I don't think DM is weak. The attacks may not have as cool animations as the other primaries but the combination DM/SR seems pretty strong to me.
1) You'll have a pretty good attack chain by L6. I'd go for Smite, Shadow Maul and Air Superiority (KB the foe then use SM before he stands up - works great)
2) A self heal by L8. No other set offers you that, so most ppl are forced to go for Aid Self. Others pick Siphon-Life + Aid Self (wich increases their survivability a lot)
3) Two PBAoE's: Dark Consumption (+End self) and Soul Drain (+acc +dmg self) that deal moderate damage.
4) A great acc debuffer: Touch of Fear
5) Midnight Grasp offers a good damage (6,3) while immobs the foe and decreases accuracy (well, all DM attacks do that)
Anyway, we're still accepting suggestions and tips 
MA surely is cool and does nice dmg but it doesn't have as good synergy as Katana/BS/DM can offer. ( I hope MAs try to prove me I'm wrong - Just trying to highlight the pros of each primary )
@False Fiction - Virtue / Defiant
Current projects - [Glaciologist - Ill/Cold Troller] [Cloudshaper - Storm/Dark Def] [Harald Wartooth - Elec/Psi Domi]
I agree that outside of the character concept, MA and SR dont have much synergy. I actually also went for MA/SR because I am a big Matrix fan and never looked back. You'll be doing great damage, and dragons tail kick is an excellent way of avoiding damage as well. True, you dont get any defense buffs/acc debuffs like from kat/BS/DM, but I can guarantee you that MA/SR is a great way to play
Blow being an Uber build, go with a concept if that's the way you're inclined. All my builds are in-keeping with their 'character' and play well once you know them.
Sure, they'll inevitably need tweaking with respecs or a penchant for pvp but they're all in all fun to play.
As an aside, a mate of mine and i play an MA/SR duo, it's great seeing both characters knuckle their way thru mobs!
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Naturally all primaries are playable and of course go with concept if you have one. The sets are quite good enough. I said DM is overall bit weak because it lacks one high damage attack that other sets have in them (DM has dark consumption instead). From game mechanics point of view, broadsword and katana propably synch best with SR because they have parry and divine avalanche. Aid self is indeed a nice addition to SR scrappers.
Ahoy! A friend of mine will soon start his career as a hero. I've already talked to him and he is sure he wants to pick a SR Scrapper ( he is a huge fan of Matrix, so the idea of dodging stuff sounds great for him ). So now his only doubt is wich Primary to pick. I said to him that DM (cuz of the acc debuff and self heal), Katana and BS (for Parry and DA) are the best choices. However, I'm not an expert SRer so I dunno how to advise him. I'm trying a SR myself when he starts and I'll probably go for MA/Katana/DM. Any tips? Thank you
@False Fiction - Virtue / Defiant
Current projects - [Glaciologist - Ill/Cold Troller] [Cloudshaper - Storm/Dark Def] [Harald Wartooth - Elec/Psi Domi]