Getting a rheumatology fellowship is easy. Salary is probably fairly similiar unless you are doing interventional pain or EMGs through PMR (procedure oriented). The lifestyle is probably better for outpatient PMR vs rheumatology (op=outpatient) because rheumatologists do admit some of their patients and do take light call from home (ie lupus flares). Inpatient PMR is probably a little harder than op rheumatology. And you have to go through an internal medicine residency (3 yrs) to do a rheumatology fellowship (5yrs total) while you only do a year of prelim medicine or transitional year before heading off to the PMR for 3 years (4 years total). I would say that those 3 years in a internal medicine residency are much harder physically than PMR. Or looking at it from another point of view, going the PMR route is much less painful if you are on the fence between the two fields and rate them fairly equally. In the end realize that day in and day out work is quite different.