Pros
Health benefits are good and they allow you to stay on it if you are on seasonal furlough (although you do have to repay it), annual and sick leave are separated and start to accumulate from your first pay period (which is good because after working here for a few months you'll want to call in sick a lot)
Cons
There are too many cons to list but I will try. Promotions are based almost entirely on seniority, so although they recognize you as a good worker, they can't do anything to advance your career unless you have been there several years. This is especially true if you are a seasonal worker since every advancement available within the local office requires you to be a year-round employee. Morale at the office is very low for a variety of reasons and I've heard multiple people say it is the worst job they've ever had. They clock every minute of your day into your time sheet, this includes you leaving your desk to go to the bathroom. They offer little to no encouragement and always have something to criticize you on, even if you are the best worker there. Seasonal workers are only given a few days notice when they are furloughed and there are often a lot of scares of early furlough. You are constantly being told to follow rules that are completely inefficient and when you question it no one can explain why it is a good policy and you're told you need to do because the policy says so. The callers are often very angry which is primarily caused by failed IRS policies and ridiculously long time frames.