For lower level i recommend a pet with double resist a heal and two damage talents. Although when you reach max level critical and block ratings are reduced so it is easier to land a critical but harder to critical. So a pet with maybe double resist defender with two damage talents, its really up to you on how you play, and what school you are. If your storm maybe a full offensive pets. Life might want some critical as well but again it depends on your strategy. Feel free to speak your mind about pets in pvp and what you think is best for certain levels.