Pros
There are some benefits to working for the IRS. You have all of the government holidays, TSP (the government's version of the 401K), and the management is pretty cool. Also, they provide a pretty fair amount of classroom learning so you can learn (or pretend to learn) the tax law that might relate to your job. Also, it seemed standard practice to bump entering revenue officers from GS-7 to GS-9 after the first year--which was about a 30% raise.
Cons
There's a certain look people get when you tell them you work for the IRS. It's a cross between pain and pity, and was never a pretty sight. If you can get over that, you'll have to still stomach the amazingly low starting pay (especially in Southern California). I had to knock on many taxpayers doors, put up with many unhappy phone calls, people crying to me, etc. I still have bad dreams where I relive some of this stuff. But then some people like this stuff; I didn't.