Zomb-
I am a therapist so i'll attempt to answer some of your questions. First off, review these links:
Accredited programs:
http://www.jrcert.org/cert/Search.jsp
Wage/Salary survey:
http://www.asrt.org/content/RTs/SurveyResults/WageandSalarySurvey/WageSalSurvey2004.aspx
Radiation therapy is an excellent field. The demand for therapists is high and the pay is excellent. In my opinion, I do not believe that the supply of therapist will exceed the demand for quite a long time, if ever. Aging baby boomers need care and there aren't that many therapy programs. Second, the amount of advancement in therapy is astounding; dosimetry, administration, education, physics, nursing, physician, etc. Granted most will require further schooling, but there is still plenty of room to grow. Altruistically, the relationships that you develop with your patients are second to none. Rather than seeing a patient once or twice, you spend every day with a patient for multiple weeks. You get a chance to get to know them, which not many professions can claim.
As for the cons, number one would be working with the terminally ill. I wouldnt trade any of the relationships ive formed with my patients for the world, but when they take a turn for the worse it makes it that much harder. Second, i'd say would be call. Call schedules differ from place to place, but it still sucks.
Should you have any other questions feel free to ask. Thanks.