Pros
You learnt while you worked, so it did work out like a double edge sword, a lot of benefit for me especially because it was in the field that I really like. I also enjoyed working with the people around me, they valued me high, they let me tried to do the best I could do. Hey, nobody's perfect, and what's more, I was learning while I was working, so that really were great! My Boss also were very understandable, he gave me flexible hours, and also depending on the second job I had, I could record my time and submit it to the next period. Overall, it was great!
Cons
No downside at all. I guess it's more or less just from my own downsides, because when you're taking classes and tried to earn extra money, sometimes it's not easy, but again, as I mentioned above - I was willing to work and my Boss gave me flexible hours, also flexible billing time. For me, that worked great!