I have both, Padshop Pro & Granulator II. Even if there’s both granular synths, they indeed sound different in term of audio rendering. It’s difficult for me to really help you because I don’t use Padshop nor Granulator for drums or percussions, I use them just for pure soundscapes and drone oriented sounds. And this is exactly why I love Padshop, because it’s easy to make it sounds lush, very smooth and velvet. More than the Granulator, which to me tends to sound more sharp, spiky and fragmented if I can say, maybe that’s why you find that Padshop lacks of punch.
But I did a quick test with a percussion sound granulated in both, even if they sound a bit different I was still able to make the percussion sound granulated Padshop as punchy as the Granulator after few tweakings, it’s just a matter of setting & experimenting with the grain duration, speed and the grain numbers.