A nitro piston air rifle is still a springer, a nitrogen spring springer instead of a steel spring springer.
No springer compoetes against a good PCP air rifle in power and accuracy, so if you want high power and high accuracy, go there.
At 45 FPE with a .25 cal JSB pellet, my BSA Lonestar will print 3/8" groups at 50 yards all day long. I shoot prairie dogs out to 100 yards with that rifle. It would be further except for Montana winds limit the range. Try that with any springer, including nitro piston, you care to use.
FWIW, I had a Crosman Nitro Piston in .22 cal, and it was 18 FPE and 2" groups at 50 yards on a good day. Got the BSA Lonestar, sold the Nitro Piston, and haven't looked back.
My BSA Lonestar blasts through a 1.5" thick pine board or 3/4" plywood with no problems. Try that with any springer air rifle. Prairie dogs are always complete pass throughs through any angle of shot on any part of the body at 100 yards. PCP is the only way to go in hunting air rifles, and mine takes the place of a .22LR shooting subsonic ammo for 4 cents per match-grade pellet....except the air rifle is usually more accurate.
Also, the accuracy I achieve is NEVER achieved with pellets commonly found at Wal-Mart or department stores. I shoot only JSB (Czech) and H&N (German) these days.
BTW, my groups are 5-shot groups, not 3-shot groups. Even springer air rifle sometimes shoot a good 3-shot group. Also, my groups are averaged from many groups, not a sweetheart group. Also, the killing power on game is in another league with a PCP compared to a springer. PCP air rifles gain power with heavy hunting pellets, not lose power as springers do.