Tried them both on test client, Terrorblade is superweak early game, that health pool is so low it's not even funny. But get some farm and a Manta Style and you'll basically be like Phantom Lancer.
Hm Phoenix was fun to play, lots of harass, but I don't like that every ability drains his health as well, that ray just rapes trough your health. Very risky gameplay and you'll probably be focused down in a teamfight. Unsure about his ult as well, it takes so long to be reborn, in a teamfight I don't see it happening because you'll just be focused.
Also, new Mana Void size:
http://i.imgur.com/Rqa9Z8e.jpg