I have found, and was told by a chaos player as well, that Space Marines do not use enough plasma and melee units to counter Chaos Marines. This is very true. Plasma weapons tear them up. Works better than a Bolter by far. Melee units counter their melee units, a lot better than a heavy Bolter, since they will,close the distance every chance they can with you. And of course Meltaguns tear up their vehicles as well. Please post what you find works best versus Orks and Eldar as well.
Everything works vs orks. We tend to be slower in animations and have a big head hit box so pretty much anything with accuracy works. Also our melee tends to be too clunky atm to be reliable in solo melee. Beware when we start mixing pistols into our dmg rotation. Our sluggas are friggen nasty when used right atm. Plasma cannons also work, but what DON'T they work on? Ran into a guild with about half of the Lsm using PC and we couldn't push anything ever due constant insta death.
Versus Eldar, Storm Bolters work really well in close range and directly compete with our shuriken catapults and the spread makes it easier to hit moving targets. Fully manned predators are extremely deadly and storm shields when used to shield tacticals and apoths while they fire is also really good. All plasma guns do a ton of damage as well.
vs Chaos - Plasma vs Orks - Plasma vs Eldar - Plasma (also surprisingly the Nathecium) Plasma was, in development and still is the great leveler. Doesn't matter what your load out is, if that blob lands anywhere near you, you're in trouble. A really nice (and by nice I mean incredibly sneaky and mean) tactic is to get clearance from your team (so you can get forgiven when you TK) just to constantly lob fully charged plasma at a point you own. You can't cap if you get one hit by super hot gas. Marines seem to be having issues with Eldar in melee. Send in the Apothecaries! The poison on the Nathecium eats into those seemly impossible to down Banshees. DoT will finish the job 8/10 times even if you die in the process. (Anecdotal - Lost fair and square to an Apothecary as a Banshee, poison finished me before the fight ended but Apo has that weapon in their arsenal so it's all fair, Apo tried to execute me but the DoT finished me off before his animation completed, sorry Brother 20 points only! So it can have its disadvantages! )
Tactical with Bolter (Stormbolter vs Eldar) - The Bolter isn´t great compared to the Eldar and Ork guns, but the Plasma Gun is even worse. Devastator with Plasma Cannon - Big Damage, Big Splash. With a Heavy Bolter you will get outgunned against more than 1 enemy. JPA with axes, swords and maces (Fists vs Chaos and occasionally orks) It´s just personal preference. Same for the GA. Just take a GA if you really want the overpriced shield, else the JPA is the better choice by far. Apothecary with chainssword and meleebuff vial. Bolter gets outdammaged by close to everything. I wouldn´t advice to use the narthecium face to face against eldar melee classes, they will break it in 2 to 3 hits.
It may be that not many players favor playing devastors cos support units dont cap and dont get as much xp as tacticals or assault classes. I happen to play devastator cos i like the plasma cannon.
For melee, I find that the additional reach of the power sword is more valuable than bonus damage or clang durability. Power fists are an absolute no. You're not hitting even an average Eldar player with that unless you come up behind them. Mid range, storm bolter. Long range, Plasma Cannon. Do not bother with the lascannon; reapers don't need to brace, so there's really nobody holding still long enough for you to shoot them.
