Alot of people tend to ask what character should they use. There is no real right or wrong on which character to choose… I usually choose my character base on these factors

• Character design. Pretty or hawt
• Fighting style. Whether it fits me or not
• Ease of use.
• Strength. If it is really really really weak character, I will skip it most of the time

I would recommend new players to use the easy learning curve characters. Some characters take much more time to learn. As such, there isnt any point to get beaten up all day when you dont even understand the game system yet  

I rate the characters base on how easy combos can be done, damage, and execution of commands.

Ease of Use 
Easy – Hayate, Hayabusa, Ayane, Gen Fu, Ein, Christie
Intermediate - Hitomi, Kasumi, Jann Lee
Kinda Difficult -  Zack, Helena, Leifang, Lisa, Kokoro
Difficult – Tina, Bass, Spartan, Leon
Very Difficult – Brad,  Eliot, Tengu, Bayman

Like most fighting games, speed is important. It is often easier to pick up faster characters than slower characters. Especially in DOA.