I'm not sleep, but one I've talked to before loves it. Gets a thrill at hearing from and seeing the transformation the OSA patients have after CPAP. And with that being the bread and better I suppose this person chose the right field.
Personally sleep is interesting as a field, especially parasomnias. However, my time on their service as a resident, I just couldn't see myself doing it. But as time marches on and life priorities change, it has its appeal in the logistics - limited to no call i.e. call that is nothing in the traditional sense of call that other specialties have, a good pay, office hours which means no weekends, and notes that can lend themselves to be fairly templated (not long winded like psych notes), and I suppose reading a sleep study is fun?? never know what you'll catch kind of a thing? Downside compared to psych / IM/ FM/ Neurology is that it'll narrow the geographic availability of jobs, there simply aren't as many and they are typically in bigger cities.
Job doesn't work out, might actually have to move. Have to tell people some times you reporting them to the state to not drive or that they can't drive until XYZ. If a hospital affiliated job, they will likely have a DME too, and if they aren't a good DME, you'll have headaches navigating those politics. Don't have a CBTi therapist to refer to or one in the department, there's a headache. Previous sleep doc or primary care punts are all on ambien and benzos, got possible clean up duty on your hands. If your base specialty is XYZ and you see a patient come to you who has significant care from XYZ specialty, you'll struggle with biting your tongue when you see management that isn't ideal.
Want to open your own practice? Will take some money and isn't a guaranteed success.
Field is definitely getting midlevel incursion, impacting job availability. Positively though, they can't read sleep studies.
The field has emerging levels of tele sleep, i.e. docs who read sleep studies from afar. Depending upon how this shakes down in the future it may or may not shake up the specialty.