In my mind it's whoever attacks first is stronger (I like to see darkrai as the dark version of Mewtwo)
Darkrai. Looks cooler, is a Dark type and is really fast.
Darkrai, I like mewtwo too but it seems to be very overrated.
Don't tell God how big your problems are, tell the problems how big your God is..
The awesome banner is by Blazaking EX.
I like them both a lot, but Mewtwo pulls ahead, due to the larger movepool and offensive stats.
Mewtwo kicks Darkrai's ass any day of the week.
aka Insanish Danish
I think Darkrai would PWN Mewtwo with the right movesets EG.
~ Hidden Power (Ghost)
~ Dark Void
~ Dream Eater
~ Rock Slide or something
Mewtwo. He's a clone! He's a badass motherfuckong clone! Darkrai's some bad dream. Who has bad dreams? Pussies.
I'm not fan of ubers but I personally prefer Darkrai.