The harder I look the rougher this seems. I would love to know what others have experienced with this creature in actual play.
I put a group of 4 level 3 PCs up against a black dragon and it was almost a TPK. The encounter took place in a natural cavern under a keep on the Shadowfell. There was a pool in the middle of the cavern where the dragon was hidden. The party consisted of a Laser Cleric, Shielding Swordmage, Tempest Fighter, and Taclord. Our party Wizard and Rogue didn't attend that night.
The difficult part about the dragon is the Cloud of Darkness power. Low level PCs have almost no way to deal with this. Cloud of Darkness, combined with the monster's high Stealth, basically gives the dragon invisibility.
I played the dragon as a lurker in the darkness, striking as hard and fast as it could and then retreating and hiding in the darkness to recharge its powers. For the first 6 or so rounds, the fight was going really badly for the players. They got hit with virtually everything I threw at them: dragonbreath, dragonfear, and claw/bite attacks. They couldn't seem to target the dragon in the darkness, and when they did they missed generating tail slash attacks. Even with two leaders they were rapidly depleting their healing resources and player dealths were looking likely.
The turning point was when the cleric successfully hit the dragon with command- dazing it and ending the Cloud of Darkness power. After that, the party absolutely unloaded with their Dailies and finally attacks started hitting. The nova was so successful that I never managed to get Cloud of Darkness back up before the dragon was dead. It was one of the more nailbitting encounters of our game.
So, despite the coolness factor of the black dragon, I would use the white on level 1 PCs. Unless the group has a way to deal with the Darkness, they're likely to get their clocks cleaned.