Pros
They hire great people, the focus is on low drama and getting things done, and the work/life balance is amazing. Guidewire's three core values are Integrity, Rationality, and Collegiality, and they really live them out in their interactions with customers and fellow employees. The focus is on being truthful with customers and each other, making well considered decisions after considering all relevant input, and treating colleagues with respect. Also Guidewire is *very* flexible with working hours, and there are numerous stress relieving options available, such as bridge, guitar playing, running, meditation, and a weekly beerfest called Thirsty Thursday. We also have started a yearly two-day hackathon where employees can work on personal projects and explore new technologies.
Cons
There's not always a lot of opportunities to work on the sexiest new technology. A lot of home-grown technologies don't necessarily translate into job skills in the wider market (although some of these are gradually being retired). Also need more career path opportunities (we have begun to address this for developers, but QA could use an SDET option).