Scope Help

Being a pcp....any scope will do....you dont need a springer airgun rated scope. Just get something with at least 10X magnification with mildots/holdovers for longer ranges. This question is impossible to answer. You will get a different answer from everyone. Make sure the scopes parallax adjust down to 10 yards too......that is a must. I use a 6-24X50 scope. The magnification helps with airguns because your targets tend to be small.
 
The question is too broad to answer. It's like asking "what car should I buy, I'll use it to drive around in?". 

What's your budget? What distances will you be shooting at? Will it be in low light?

For me, it wouldn't be worth putting an expensive scope on a Marauder. Some of the scopes mentioned are more than your rifle and you wouldn't be able to make use of their capability.

Hunting and target shooting are conflicting priorities. Typically, hunters want something lightweight with a wide field of view. They don't need high power glass for shooting squirrels at 30 yards. Target shooters typically want high power scopes and they are less worried about the weight. You can hunt and target shoot with any scope but it won't be optimal for one of those activities. 

That's a long way of saying that you'll get conflicting advice if you don't narrow down your criteria. My advice would be to not ignore weight if you plan on walking in the woods with your rifle. The Marauder is already relatively front-heavy...

 
He means how and where you adjust focus. 
Some scopes you'll twist the front of the scope (AO) Others have the focus knob on the side of the scope opposite the right/left turret adjustment (Side Focus or sometimes referred to as "SWAT")
You can easily tell what the scope is by looking for the yardage numbers. They'll be printed on the front bell or on the side knob. 
Here's 2 examples...
AO - http://www.hawkeoptics.com/panorama-3-9x40-ao-10x-mil-dot.html
SWAT - http://www.pyramydair.com/s/a/UTG_3_12x44_AO_SWAT_Accushot_Rifle_Scope_EZ_TAP_Illuminated_Mil_Dot_Reticle_1_4_MOA_30mm_Tube_See_Thru_Weaver_Rings/3493