Stepping up>>>>>
I really cannot be of much help with he pusher style jets as far as performance. My experience with pusher prop type planes has indicated a loss of performance in the thrust department.
But, I believe that the more important thing in your case is the statement , " flying a trainer, -- almost have it down pat. "
Anytime that you 'step up', you will have two major issues to deal with. Number one is disorientation in the air and speed. The disorientation is a BIGGIE. Jets in general have sleek lines, little frontal area and profiles that can confuse it's attitude to you in a heartbeat, the speed factor just compounds the problem.
I have watched several of the GP F-15's fly. They all have landed a little on the hot side, but are stable in the air and are easy to become disorientated with if you are not careful. I have also watched the pusher F-16--disorientation here also....
If you do decide to take on one of these prop jets as your next choice in a model, get on a buddy cord with someone that is comfortable with fast sleek models until you are confident in your own ability to handle the speed and stay orientated to the models attitude.
Also learn the tricks of the trade about how to become reorientated to the model quickly in the air, i.e., waging the wings, pulling up(if the model goes down, you are upside down and need to roll over) etc, etc.....
Good luck
Rod