If you want to go through ETPS then QQ is the way to go! QQ are the only company that will pay for ETPS. Other companies will provide routes to FTE, but they are more protracted and you won't end up with the same condensed training that ETPS offers.
With that said, working for other companies (BAES, MA etc) may well provide you with a different skills set which would set you up well for a future career in aeronautical engineering (or what ever you end up doing).
Don't forget, even if you do work for QQ, there is no guarantee that you will get on ETPS, like others say, competition is fairly harsh. You could work there for 5 years an not get on the course, or you could get on the course and then get chopped (a good and hard working engineer who passes the selection shouldn't have to worry about that though
).
I personally wouldn't worry about spending money on PPL etc, I don't think it would make much of a difference (well, no more than a good rounded education on general aeronautic, maths etc).
Good luck!
FTE Pruner