Pokemon soul silver and heart gold is better!
Pokemon black is a good game in it's own right, compared to the previous generations, it's a cheap knock off. Pokemon black has a great story line that you are the key of saving the Pokemon world (like any other Pokemon game).
In this game you fight team Plasma, who themselves are not evil but want to liberate Pokemon from humans to protect them.
Pros of this game:
The story line is new and fresh.
Graphics are great from towns to Pokemon.
Tm's are reusable like Hm's.
You have two rivals to fight.
New Pokemon are added in.
Experience is increased when fighting stronger Pokemon.
Dream world allows you receive many Pokemon (like the poke walker) but, with new abilities.
Cons of the game:
Catching all those Pokemon are tedious without major help.
Some of the Pokemon designs lack creativity.
After the game is beaten there isn't much to do (unless you have wifi, however there isn't much to get done).
There are very little Pokemon trainers to fight again (other than the elite four).
You can only use dream world once a day for an hour.
Why is Pokemon Soul silver and Heart gold is superior:
The game allows veterans to relieve their childhood memories and, newcomers to experience what they have miss. This game is filled with many features like the poke gear, so you can battle trainer you've exchange numbers with as many times as you like. You can use the poke walker as many times you can a day (unlike Pokemon black and white's dream world which can only be use an hour a day).
The battle frontier allows you to train your skills as a trainer and it has good move tutors there to teach moves that are hard to obtain. There are 16 badges to get (unlike the others where you obtain eight) You can re-battle gym leaders (in Pokemon black and white you can't). Your Pokemon follow just like in Pokemon yellow. You get to face the previous champion Red at the end.
The glitches of evolving Pokemon that require trading without trading at all are in the game so you won't lose you chances to get a Sizor or a Gengar (Pokemon black and white they took this glitch out)