As a Pediatrician:
Things I like about Pediatrics:
1) Patients who get well. Kids mostly come in two varieties, the ones who aren't really sick and the ones you can fix. Pediatric cancers might be some of the most satisfying disease in medicine: you use all of your powers and all of your skills and what was a dying child gets to live a full and happy life. Adults often can't be fixed, and when they can many of them aren't really so much 'well' as 'they'll make it another 5 years'.
2) Patients who are fun: When nothing is wrong with a child you make funny faces at each other. When nothing is wrong with an adult they ask for Dilaudid
3) (almost) no drug seekers
4) (Almost) no gyn exams
5) significantly less polypharmacy
6) Patients almost universally have at least SOME resources for follow up, prescriptions, food, and shelter. And when they don't its treated as a problem that the social worker has to help fix, rather than a reality you have to deal with.
7) Lawsuits are really rare. Average Pediatrician is sued once per lifetime.
8) Bad outcomes are treated as an enemy: Life always ends the same way, and they say you have to make peace with it if you go into medicine. Well Pediatrics is the exception to that rule. It was important, at least for me, to know that I would pretty much always do everything, and always fight as hard as I could for every patient, and it would always be the right choice (NICU and PICU are the exception to this rule)
Things I hate about Pediatrics
1) The pay is bad. If you don't want to do NICU, PICU, or outpatient general pediatrics with nursery coverage you might not break 160K. If you want to do a subspecialty the pay is truly horrendous: three years of extra training to make 120K for 55 hours/week. Pediatric subs is the rare medical career where you'd actually be financially better off as a nurse.
2) You are legally and ethically responsible for AMA decisions. When an adult wants to try healing crystals rather than chemotherapy that's on them. When they want it for their kid you are responsible for precisely straddling the line between being overbearing and negligent, and calling CPS the second that you cross it.
3) There is not a lot of research. It is really, really hard to do experiments on kids. There are good ethical reasons for this, but the consequence is that when kids get sick the data you're working with is often, when you really look at it, not much better than an educated guess, particularly for the more critical patients. This also makes training worse, because in the absence of data attendings like to yell at you for not doing it 'their' way.
4) You make decisions without data. your patients are mostly nonverbal, they can't pee in a cup, and they scream at the top of their lungs through the physical exam. Also, for both good and bad reasons, Pediatricians are very lab/radiology phobic. It can make what would be a simple diagnosis like 'UTI' into a mess of clinical criteria and return precautions.
5) The residency kinda sucks. Pediatrics splits off into a lot of different directions, with a large proportion of graduates becoming clinicians with nursery coverage, another big chunk working inpatient, and another huge chunk specializing. This is as opposed to IM that can basically say that they're not really going to do real clinic, or FM which doesn't really feel the need to prep you for inpatient at a tertiary care center. The result is a residency that works you 80 hours a week most of the way through to try to get you ready for any of those things, and yet fails to do so because there's not enough time to devote to any one of them. It also might be the most micromanaged residency, because the fear of a mistake in Pediatrics is so much higher than in adults.
6) You will be sick. You will be sick all the time.
7) When they happen lawsuits are really bad. Pediatric lawsuits are emotional wringers that end in the highest payouts of any specialty.
8) Bad outcomes are the worst thing ever. If it was unavoidable its an emotional nightmare. If it was even arguably avoidable that nightmare will be compounded by the most vicious M&M process in all of medicine.