Pros
Different opportunities available if you are unhappy with your job. Many jobs permit working from home. Donated sick leave if you run out of your own. It is a union job so managers cant just fire you or pick on you. Potential bonus available. Holidays, good vacation and sick time. Great pension if you put your funds into it as IRS will match some percentage of it (free money is always good) NOTE: my experience / job does not cover all positions/types of work
Cons
Tons of paperwork and administration work take time away from the actual job. A bit too much pressure on finishing tasks when IRS is short staffed and/or equipment is old. Lots of old equipment. Many jobs are one person jobs: it is 'yours' and no other person does your job when you are out sick/on vacation so work piles up. IRS tries to save money by finding and securing new vendors, software, etc. The time it takes to learn the new steps is too much as it happens too often. There was one piece of software I never learned - I had no time -- and it was recently replaced. Great, avoided wasting time that eats into my regular 'real' work with that one. New persons will miss out on interactions with older staff due to "work from home". I learned most of the job from interacting with coworkers and/or listening. It takes about 5 years to really learn the job, the software, the law, the rules, etc