I have both and they are both similar from a competitive standpoint with each having individual pro's and con's. I would recommend taking a look at the two packages and seeing which offers classes that you play. For instance if you play DK, Mage, Warlock and Priest, you'd be losing out if you went Tuan but would get all classes covered with GladiatorSuite.
Biggest recommendation though with CR's in arena though is disable all CC and learn how to single target & focus target CC & interrupt. In addition, for major offensive & defensive cooldowns, use those manually. Competitive arena is far too varied and you need to coordinate with your partner far too much to let the bot handle all of this for you. I pretty much just let the CR run my core damage rotation and I handle everything else.