Re: 4 shots in 1/2 second, Man you don't just double tap em, you double double tap em!
If the BG gets up after that, give him the other 3 and reload while running!
But as far as 777 goes, Overall I'd say good experiences. As you mentioned the cleanup is easier than BP or pyrodex, and you get a little more thud for the same volume powder charge. I know a couple of guys that won't shoot anything else just because of that. Some people don't like the smell of 777, I can tell if your shooting 777 or pyrodex as soon as the smoke from the first shot hits me...I think it has a sort of chemical smell, but 777 isn't sulfur based so you don't have the rotten egg smell.
Pyrodex is a couple of bucks cheaper per pound around here so I've stuck with it for years. But theres nothing inherently wrong with 777 and I shoot it in my inline from time to time and if I take a notion to CC the Remmy I'll use it for a special SD load that I worked up that is very reliable and packs a nice whump on the target when I decide that its time to put fresh powder under the lead. If I'm just target shooting I get distracted talking with my shooting buddies and I tend to get a little heavy handed on the loading lever. But brazosdave said it right though, just seat the ball on the powder and you'll be fine.