I think Nephrologists are some of the brightest physicians out there. The kidneys are one of those organs whose slightest nuances can have drastic effects on the entire body, and renal guys have to be damned good internists as well as subspecialists.
Fellowship is usually 2 years except for some places which require a third research year. Believe it or not, they acutally have a fiew procedures (femoral permacath placements, kidney biopsies, and at some centers these guys PTA/stenting of the renal arteries). Aside from top programs, matching is not difficult. Why? One reason is the intellectual rigors of the kidney -- many people, except Nephrologists/budding nephrologists, don't really understand the beans. Second, and more importantly, is the nature of the practice. As a general rule, renal patients are really sick and often need dialysis emergently. And this will keep you up at night. And, for the most part, you are treating and dealing with patients who unless they can be transplanted have a terminal disease, so you often times need the Heme-Onc docs philosophy about providing care for your patients.
However, private practice nephrologists do REALLY well $$-wise because of the current situation regarding reimbursement for dialysis and regulations regarding ownership/management of dialysis centers. Many cities often have multiple large nephrology groups that turf it out and things can get heated when $$ is at stake.
From what I read and hear, it's a field in much demand.
