Need some advise
I have the STE3 and 3 x 600EX-RT. Love the system. Flashes do ETTL for me when I am shooting on the go. When in a studio type situation and shooting portraits I am always on manual. I will choose manual over ETTL any day if I have time to set up.
If I had the space for a permanent studio I have strobes. Better yet I would have both, strobe set up and RT ETTL flashes but for what I do the flexibility is important. If you are just shooting portraits save your money and just get the YN560's, etc.