I'll respond as a current second-year ID fellow soon to be transplant ID attending...
ID is in a interesting and difficult place right now. Fellowships are having difficulty filling their spots, even some of the top programs, due to the low reimbursement. I think the demand for ID docs will only grow given our role in antimicrobial stewardship and infection control, as well as the growing field of transplant ID. Thus, via supply and demand, at some point reimbursement will increase and ID will become a more competitive fellowship.
As it stands currently, you will be very busy as an ID doc due to the general shortage of ID specialists...consults are a mixed bag. There are many consults where the diagnosis is known (i.e. cellulitis, pneumonia, osteomyelitis, etc.) where the team just wants you to basically setup the discharge for them. These are not educational and become somewhat draining. However, this is offset by another large portion of your consults which are on patients who have a likely infection and are immune compromised and the diagnosis is unclear. These diagnostic dilemmas are our speciality and also the most rewarding part of ID. Like any other speciality, we have our less exciting consults but the core of what draws people in medicine to ID remains. The focus has switched from HIV/AIDS to transplant with our improved antiretrovirals, but there remains a strong demand for internists who are specialized in the art of diagnostics and can diagnose and treat both common and esoteric infections in sick, high-risk patients. I think going into ID now will payoff in the future if it is truly a field that interests you.