Job placement would be equal top of my list along with your concerns about the quality of training and being partnered up with someone of similar experience. From what I have heard there are many TRTO's that are mere production lines. Then there are others that are also job agencies so have a vested interest in getting you placed.
If you can try finding out which airlines have hired from the various TRTO's and whether they give references or put your name forward. Ask them what you need to do in order to get recommended as well.