http://www.wizards.com/magic/tcg/produc ... roductinfo
The new commanders all have some kind of unique mechanic specifically made for the format.
You have some that care about mana spent to cast:
[card]Jeleva, Nephalia's Scourge[/card]
Marath, Will of the Wild
Prossh, Skyraider of Kher
One that gains life even when in the command zone:
Oloro, Ageless Ascetic
And one that has an enters the battlefield trigger and an ability to put him onto the battlefield directly from the command zone:
Derevi, Empyrial Tactician
All of them seem interesting to play around with!
n
Sadly I have not had the chance to play with any of the decks so far

Do you like/dislike the new Commanders?
Are the other cards any good?
Did we need more Sol Rings?
What do we think about the day1 errata on Marath?