Re: benjamin nitro
I have a Benjamin Trail NP in .22 and it's pretty sweet. Super quiet with the nitro piston. The only pellets I've shot out of it so far are Crosman Premier hollow points. Out of the box accuracy is terrible, but the groups started to tighten up after maybe around 200-250 pellets through the barrell for break-in. The 3-9x40 scope that came with it is an AO mildot scope that seems to hold zero, but is a terrible pain to get zeroed in because the adjustments are terrible-- think anywhere from 1/64 MOA to around 10 MOA per click.
Longest shot so far was a hit on a big dove at 79 yards. Feathers went flying everywhere, but the dove flew away as if unharmed, so I don't really know what to make of that. At around 25 yards it drops Mynah birds as though it were the hammer of Thor. The noise of the impact of the .22 pellet hitting a bird at 25 yards is actually louder than the sound of the shot, which is pretty cool.
All in all, I'm happy with the purchase.
Wish I had some experience with the .25 to share with you, but I think the .22 would probably suit your needs and you will have a lot more pellets to choose from.