When I transitioned from CT to CS2, I had been maining Ragna, but I was inspired by Zakiyama and Buppa to main Hazama, and from the first moment I popped the cd into my friend's PS3, I used only Hazama. It took me about a night of practicing basic combos to get a good flow with Hazama going to where I could hold my own against my friend who mained Jin. I could say I've almost mastered him now, but it seems like every day I learn something new about my combos and overall metagame that I hadn't known before. I don't think I'll ever be good enough to even last a round with Buppa or Zakiyama, but I think I'm pretty decent. :]
I don't have enough money for the Vita, so I haven't had the pleasure of trying EX Hazama or Ragna. Although, I'm really anxious to try and main Relius, since I hear he's simpler to main than Carl is without a fight stick.