Always remember, you didn't pay for my opinion.
I have a .25, I just bought a .22 for a couple reasons.
Mostly I punch paper. Being a cheapskate, I look for economy wherever I can get it.
JSB .22 per tin - 500 for $19, .25 for same pellet, 350 for $19, Air usage, don't have any stats, but you get more shots out of a .22 before airing up the gun again. Accuracy is about a push.
There's a huge variety of pellets in .22. .25 is catching up, but still, new inventions come in .22 first typically. If you want slugs, .22 has a better variety.
Mostly, if you want to dispatch small pests, our UK neighbors take rabbits at 30 or 40 yards with sub-12 foot pound guns. A .22 pushing 28 or 30 foot pounds of energy is plenty to dispatch said critter. A .25 pushing mid 40 foot pound energy could be considered unnecessary.
If you pump, go smaller. If you have a compressor, it doesn't make that much difference. If you check the Marauder specs, a .22 is rated for about 30 shots per fill, where a .25 is about 18 shots per fill if I remember correctly. That's a BIG Difference, because hand pumps aint all that fun. It takes 100-ish strokes to fill my Marauder with a Benjamin pump. Those last 25 or 30 pumps are not easy and get the blood pumping. You'll need to take a rest before you can shoot again.
good luck