When it comes to voice acting its better to make a voice aimed toward the character you're playing, doing an imitation of a pre-existing character is usually best saved for parody. If your impression is bad however it can become a brand new voice that is unknown, I also find its better to try and do impressions of people over characters because you always want to sound believable unless you're aiming to play a zany cartoon character, hope my advice helps you grab many roles in the future!