Maybe I don't belong here, but this thread is very discouraging.
There are pros and cons to any specialty. Radiation oncology has its disadvantages. Some of those disadvantages are that it's a small competitive field with limited residency positions and with a job market that fluctuates.
You do have to be a very competitive medical student to obtain a position in the field. Even so, you are looking at applying nationally and matching randomly. Location is not something that you get a whole lot of say about.
There are some less than ideal (and outright bad) programs out there. Some of these are the big name programs whose names are thrown around on SDN all the time. This is because the faculty and/or research at some programs are big name, but that doesn't necessarily create a strong teaching or research environment for residents. If the attendings spend all their time generating papers, guess who has to pick up the slack in clinic? Further, most of the contributors to these "rankings" threads are medical students who overvalue location and prestige, and have little clue about what makes a good training program. Nobody has said in this thread that you need to go to a "top 5" residency program to obtain a position near a big city. That is hyperbole. What we have said is that big, desirable cities are competitive job markets. What we have also said is that where you went to residency is just one of many factors (probably a smaller one...) pertaining to what job you get after residency.
Some years there are many jobs, and other years there are not. This is at the whim of the overall job market, and is completely out of our control. Since this is a small specialty, the job market can change a lot within the span of 5 years, for better or for worse.
At the end of the day radiation oncology is an extremely competitive specialty in which to obtain a residency position. The specialty is not for everyone. Of all the medical specialties, I love radiation oncology, and I would do it no matter the drawbacks I listed above. But, I'm not going to try to convince anyone that they need to do radiation oncology. That's something that you have to decide.
If location and lifestyle are most important to you, there are other specialties with good lifestyles that are much less competitive. For example, if you want to match in PM&R with an application competitive for radiation oncology, you will have your pick of positions. Psychiatry is similarly non-competitive, and I hear has a strong job market. Primary care is exploding with demand, and with a strong medical school performance you can go anywhere you like. There are many more examples.