Marauder is nothing like a rogue, they are like medium armor fury warriors.
-Fury/Rage Mechanic
-No Stealth
-Only similarity is Dual-Wield
Operative is the closest port to a rogue you can possibly get.
-Backstabs/Positional Attacks
-Stealth
-Poisons
-Very Reliant on Stealth Openers for Burst
Assassin is like a Light Armored Death Knight with Stealth
-Dark Charge/Lightning Charge/Surging Charge
(Blood Presence, Frost Presence, Unholy Presence)
-Force Pull (Death Grip)
-Can tank and dps
-Melee and Ranged Abilities
-Low Reliance on Stealth for Survival
On a further note, everyone and their mother are rolling Sith Sorcerers and Assassins. Therefore, if you want the class that most plays like a rogue and don't like thousands of other people having the same class as you, go with operative. Good Luck, Have Fun