OK. I just loaded, for comparison, 6 rounds. Two 2400 7.0 grains (as recommended starting point by Alliant in Handloads.com), two Power Pistol 5.8 grains and two Unique 5.1 grains. All with 158 gr LRN Speer bullets. Shooting was at night.

Wanted to feel the power in the flash and recoil. Unique was something of a jump with a bit of a spark coming out. Power Pistol was a little more jump and more of a flash. 2400....was a almost no jump and almost no flash.
Even my dad, who was sitting inside my house, ask what I was shooting. He noticed the first two were pretty loud while the last two sounded like almost nothing.