The three main routes all offer similar job prospects, but the main advantage that route 1 offers over the other routes is the job guarantee you will receive before you start training. You will receive a job offer with route 2 either once you've been upgraded to the mpl course after ground school, or once you meet the standards after the advanced flight training phase, which also happens to apply to route 3. You will only receive an offer through "route 4" (I'm highlighting this because this is effectively OAA's whitetail course) once you pass easyJet's selection process after training.
This is my understanding of how the process works, if any of this info is wrong then feel free to correct it.