I see you ordered the Gamo Urban. Good choice, but if you decide to go after a Marauder, consider -
I have the .22 Marauder. At one point, I had it tuned to shoot Crosman Premier Domes (Cheap ammo) at about 830 fps, getting 40 shots per fill. Right now, it's throwing JSB Exact Heavies at 830, Crosman Premiers at about 900. Getting 20 shots per fill. Very quiet and very back yard friendly. Very adjustable for whatever you want it to do.
With the right scope combo, I can get sub 1 inch groups at 50 yards.
One reason (IMHO) not to get a .25 is simply the power. Remember that you've got to stop the pellet before it leaves your yard. The .22 adjusted for the Crosman Premiers only gives about 21 or 22 FPE, and drops quickly as it flies. Still hits with enough power to punch paper all day long. Economical with air.
By the way, shortage of used Marauders is a good sign. Most people that buy one, never let go. The Gen 2 Marauders are vastly superior to the Gen 1's, so if you find one, make sure it's a Gen 2. You can usually identify a Gen 2 with the adjustable comb on the butt stock.
Hope that Urban works out for you. It didn't exist when I bought my Marauder so not sure which I would have chosen at the time.