At full power they are a little loud, but generally the loudest thing about the marauder pistol is the impact of the pellet.
My marauder pistol with a lightweight hammer and a regulator makes a lot less noise than it did stock. I also have it tuned for 12fpe for 50 shots.
If you use one at factory power it will make a little noise. There are moderators before them if you want less noise. As far as comparing it to a Springer, it really depends on the Springer. It's a different type of sound, but they are comparable.
A high quality pump will fill faster and smoother than a cheap one, but they take a lot less pumps per fill than a gun with a larger airtube.
In my backyard and with my neighbors it's fine. However, your backyard and neighbors maybe not.
The P-rod has one of the lowest Db of guns in it's price range out of the box.
Most of the noise from a spring gun, depending on the spring gun, will be heard by the shooter because of all the mechanical noise of the firing cycle.
As for the P-rod you can add an aftermarket "noise reducing device" like the one made by www.tko22.com. Most all spring guns do not have the capability of furthering noise reduction.
This is the model I have used on my P-rod and yes, the impact of the pellet will exceed the noise the shot makes.
As for filling it, it's pretty easy if you use a quality high capacity hand pump unless you have physical limitations. The air tube is only 65cc,
