Simmed your character and got the following numbers:
Marksman: 25579 DPS
Survival: 28137 DPS
Keep in mind this is straight up single target deepsing, and doesn't account for encounter mechanics. You're probably better off going Marksman on Brackenspore for instance if you're doing flamethrowers. Unless your guild is struggling with killing adds fast enough on Imperator I would probably go Survival for most fights though.
If you only care about numbers, then Survival will be better for you most of the time.
Marksman usually runs Lone Wolf and Stampede is better for Lone Wolf since you get an extra pet out of it.