.22 OR .25 ???!!

Both great calibers and you cannot go wrong with either! That said, if you are going to shoot both calibers using 25gr pellets then the JSB 25gr Redesigned have a better BC than it's sibling .25 25gr pellets. If shooting slugs, then .22 as there are way more options to purchase. .22 ammo in general is much less costly to shoot and with it tough to find or buy ammo now....
 
my opinion is FPS being equal bigger hits harder .. doubt you be wanting to fling around a heavy slug in your yard if you got neighbors within 1/4 mile ... same goes for the .25 imo its twice the energy more or less than a .22 i can get away popping something in front of the chicken coop or privacy fence with a .22 in the yard .. .the .25 is iffy, it might just punch through and ding something in the neighbors yard in the back .. out front towards the pasture though i can .. so its like that .. what and where i shoot will largely determine .. other than that if im heading to the woods i want the hardest hitting gun i got ..
 
Depends if you’ll shoot pellets, slugs, or both. As far as pellets both the .22 RDM and .25 Exact Heavy outperform either .30 pellet in the wind - highest BC .25 Exact Heavy, then .22 RDM, then the .30 pellets (44.75 and 50.1). 
If shooting slugs probably because there are more choices the .22, but generally terminal performance is similar unless you do enough mods on your .22 to shoot very heavy slugs but the selection is minimal. For commonly available slugs at reasonable prices, the heavier .25 are what I shoot in my Impact - the 43.5 grain NSA. BC is “only” about 0.110, but they get the job done out to 200 yards, and are $18.95 for 225 slugs.
 
.22 cal for rimfire use, where firearms are most appropriate and legal

.25 cal for suppressed airgun use and where firearms are not appropriate (like shooting a coyote in your backyard in town)

I have a .20 cal Sheridan Blue Streak which is the appropriate thing to use around buildings, animals and other high liability areas as it has variable power due to its multi-pump nature. I had a .22 cal Benjamin as a teenager, but I like the .20 cal Sheridan better as it works better overall at the 15 FPE level both rifles have. The Sheridan is a flatter shooter with a higher BC and SD and longer range for the same pellet weight.

Very powerful .22 cal airgun with variable power for a "one gun that covers both rimfire and airgun duties" scenario if I was restricted one small caliber rifle that had to handle both rimfire and airgun duties. Since that is not the case with me, no need to have one. YMMV.

Most places, like here, do not have .25 cal pellet availability. If buying pellets locally, the .22 cal will be the only choice for most people. I have never seen a .25 cal airgun of any type for sale locally in any of the shops that carry airguns. .25 cal airguns are basically unknown outside of the airgunner community.