Pros
The SEC has excellent pay and benefits. In fact, the SEC is among the most generous in the federal government. If your only motivation in life is to get paid well and have job security, the SEC is a good place. If you aspire for something greater, don't settle at the SEC and keep looking. The Union will be your best friend while you are the SEC.
Cons
I have 15 years of professional experience in the federal government. From my experience, the SEC is the worse managed agency I have ever worked. First, the SEC management horrible. They may be competent attorneys, but they are terrible in managing people. I am not going to use the word leadership, because this does does not exists at the SEC. Second, the SEC has a very toxic environment and low morale. You can gage this by the fact that nobody interacts in the hallways - everybody has their door closed. When you get in the elevator nobody says hello. Collaboration is totally discouraged among divisions and offices. If you like working 8-9 in a cube by yourself and want to call this public service, then this is your place.