Pros
Through Volt, I was able to secure four long-term contracts with Microsoft over about 3 and a half years. From the time I first contacted Volt until I completed my final contract, the staff was always friendly, professional and supportive. My Volt rep approached his job with enthusiasm and a strong work ethic. I was also please with the benefits package Volt offered. Though I paid for half of my health insurance premiums, I felt it was very fair given the hourly rate I was earning. If you've got the skills and a professional, friendly business approach, you can earn a very good living.
Cons
Working on contract means you need to be flexible to available opportunities. You can't always expect to land a "perfect" contracting position. I worked at Microsoft as a Volt contractor. Some teams were great to work with at Microsoft, some were not. Depending on the economy, you may be unemployed for a time before any contract positions are available that fit with your experience.