I HATE the Jockey, so he's clearly the best of the new infected.
He's small, moves fastish and seems programmed to find cover effectively. He's a little shit to spot early and kill plus he ALWAYS jumps someone at the WORST POSSIBLE MOMENT. So far the Jockey has caused survivor death more than any of the other infected, usually indirectly by breaking up the group when they need it least.
As a gameplay mechanic he's flipping effective, but I hate his little giggling guts because of it.
Charger and Spitter are a bit of a pain, but rarely cause fatal attacks. Except once when a Charger managed to kill all four survivors at once by knocking us into deep water, that was annoying but a one off, we learned from it and el chargico hasn't scored a kill since.