Pros
Nvidia is a challenging environment to work in, and does not fit everyone, but if you want to be surrounded with leaders in the field, people that developed the first patents in graphics and chip technology, then it is the right company for you. You will be pushed to your capacity and then a bit beyond, especially as you come up to speed as Nvidia is not a company that will hold your hand, it puts you in the middle of things and waits to see where you float to the top or sink to the bottom. As this baptism of sorts is common within all Nvidia departments, you tend to keep the hard dedicated people around and the others quickly fall off. Can't go wrong with Nvidia on your resume, as work cadence is second to none - new projects are constantly around you so there is no shortage of new areas to grow or get exposure to. The Company execs know how to win, and have a proven track record to do so, just ask S3, ATI, 3Dlabs, SGI...Honest company with its employees, straight forward information from exec team, and even has a pet friendly policy
Cons
The same benefits are also the downside. Nvidia is not for the part timer, not for the person looking for all weekends off and 9-5 work week hours. The projects are relentless, the time lines are demanding, but the rewards are plenty. There is no "do it tomorrow" mentality at Nvidia and as such, the hours can be long. Since the pace is so fast, training is very quick for new employees, and it's up to the individual to find out what they need and to develop.