We're switching to this system for our new campaign which starts today. And lingering wounds if you drop to zero.
Oh, I love lingering wounds. Keep in mind, though, that you should apply them to monsters and NPCs as well as PCs; there's nothing so amazing as ending a fight after the cleric gets a spear through the chest and a collapsed lung and then, in a fit of perfectly-timed rage, the barbarian lops off the thrower's arm. That was just so delicious it had the party cheering, as the cleric coughed up blood and the bard saw to her wounds.
I'll say, however, that I do lingering injuries just slightly differently than presented in the DMG.
A creature takes a lingering injury when one or more of the following occurs:
1. When a creature takes a critical hit, the attacking creature rolls 1d20; on an 11-20, the target takes a lingering injury.
2. When a creature drops to 0 hit points but isn't killed outright, the attacking creature rolls 1d20; on an 11-20, the target takes a lingering injury.
3. When a creature rolls a natural 1 on a saving throw against a trap or magical effect, the DM rolls 1d20; on an 11-20, the triggering creature or creatures take a lingering injury.
4. When a creature fails a death saving throw by 5 or more, or automatically fails a death saving throw for any reason, they take a lingering injury.