Pros
First, I will cover the pros. There are good people working at BIS. I have formed meaningful relationships there and for that I am grateful. There are also benefits including health insurance, visual insurance, dental insurance, 401K, etc, and you will be eligible fairly quickly.
Cons
Moving on to the cons, there are several and they outweigh the benefits. If they want you to travel, you will be made aware with very short notice. You will be approached maybe one or two days before departure which gives you very little time to prepare. This might be manageable for a single person, but if someone has a family or other responsibilities, this can be very difficult. Moving on to training. There is absolutely no training. You are left to figure things out for yourself and when you mess up due to lack of knowing what to do, you will be treated like you're stupid, thereby being left feeling insecure. This adds more stress to an already stressful environment. Also compounding more stress, BIS is run very militaristic and employees are verbally abused and reprimanded publicly. This brings the companies professionalism very low. If you are wanting to get into IT, BIS can be a good place to start, but be aware that if you don't impress the right people you will have problems. Take heed to the negative reviews. I ignored them and left a very good job, making more might I add, hoping to further my IT career, and ended up regretting it.