Don't know your planned uses, chances are you would never know the difference. My experience with the .25 is very limited. IMO, you pay a small price in additional recoil, noise, and air efficiency, for an even smaller gain in power.
Get the .22 caliber. I had a Daystate Huntsman Regal XL .22 caliber and used it for backyard/woods squirrels and plinking; and for target practice at the range. The .25 caliber Revere is a bit less than other .25 caliber brands in terms of FPE, and I’m not sure it’s worth it. It’s a cylinder gun with a comparatively small air reservoir, so the shot count may be less than you desire/need. The .25’s drink air and with a smaller shot count, you will fill more frequently than the .22 cal. I also have a lot of respect for the accuracy of the JSB 18.1 and 15.89 for the Revere .22 cal.
That gun is not made for big power or super high shot count. It's suited for .177 and .22, IMO. I've wanted a .177 Huntsman Classic since Ted reviewed one years ago.
I bought the .25 in a Regal XL, and it has enough power to put a Hades through a coyote's chest at 40 yards. For pellets this rifle is a perfect balance of power for accuracy. A .22 would probably give you more pellet options, but I reserve that caliber for rimfire.