Until our DC Cotrell learns how to best utilize the Chargers' strengths (the aggressive pass rush), I would probably stay away. If he figures it out, then they will probably be a decent unit. However, he hasn't proved it yet, and until he decides to become an attacker on defense, the Chargers D, both in real life and fantasy-wise, will be largely inconsistent.
If you're comparing them to last year, they're definitely over-rated. But almost all the pieces are still there, so it's not a matter of talent, but rather coaching. But this week is the time to use them if you have them. Both the Pack and the Pats have good passing games, so they ate us alive. On the other hand, KC doesn't appear to have the same caliber QB/WR core, and their strength is (or was) LJ, so I think it plays well into the Chargers hand. Well, at least I can hope....