I'm level 31 Powertech now. Ive tanked primarily with a prot paladin in wow and now I feel the Powertech is similar with its aoe tanking. The extra endurance is a waste, we are talking 3%. So for example you have 10,000 you will receive an extra 300 up which is a joke. The jet charge is never used. You receive sonic dart which does aoe aggro on any second group you need to pick up. Yea it's a cool ability but the points are better spent on damage mitigation like Shield vents and ion screen or some star dps. Focus on: damage mitigation and flame bonuse. Also in pvp the damage reduction is the same as pve. So you are basically indestructible. Just my 2 cents. The only question I had if given the choice between shield vents or ion screen, which would you choose. I went for ion screen because shield has such a low % to begin with whereas ion screen is a flat 2% Damage reduction.

You get the second companion on tatooine around level 26-28. Follow your class quest line. Im assuming you know you get the droid which is technically your second companion when you get a ship. But he can't quest with you so I'm also assuming you want to know when you get someone other than Mako... In which case it's on tatooine as I posted above.