I took a good, hard look at all of the classes and advanced classes, and i honestly think that the best of them all are the Powertech/Vanguard and the Sorc/Sage. The Powertech/Vanguard in PvE make great tanks (due to the ranged attacks, which in some cases help keep agro), and the fact that they can take a realy hard hit if spec'd in defence. In PvP, The DPS spec's, and even some Tank spec's, could completley change the tide of war in any of the Battlegrounds (depending on what you do in different situations). The Sorc/Sage in PvE have a great DPS output aswell as being the most powerfull healers (In my opinion). In PvP, They have a great set of abilities that help in battle. Force Sprint gives them mobility, while the Static/Force bubble can defend the user from attacks while they sit there and blow their cooldowns.
Everyone is entitled to their own opinion, and this is just mine. Feel free to correct me!