Greetings Paul-3 and welcome aboard.
Hardcase's use of "snappy" is as good as any. And, mykeal is correct about it being a comparison of apples and oranges. You're familiar with the kick (felt recoil) of your Pietta -- now, assume that you been wearing invisible padded gloves all along while shooting your .44. In your mind's eye, take off the gloves and you'll have an idea of what a typical (if there is such a thing) center-fire smokeless powder pistol may feel like.
In reality, you may find a little .25 auto seems to have more kick than a .357 mag. It's because the .25 is usually found in small pocket pistols and the mag in larger revolvers. It's not the so much the energy of the round but the weight and grip of the gun that determine kick.
Remember, you're after consistency from your gun -- don't think of it as shooting high but as the sights being set low. Thus far, you've been experimenting with various powder charges -- how about different projectiles. Have you tried conical bullets? You'll get better accuracy.