Pros
One of the best reasons is the location: Austin TX, home of the University of Texas. As an extension of the location is the overall company culture: relatively laid-back and loose, yet professional. The benefits package (401 K, health) are very competitive and appealing in these times of growing health costs - especially true for health coverage. Mobilizing the employees themselves to recruit new grad candidates is also a plus, as the process allows the younger and senior engineers/employees to promote the culture and select among _best and the brightest. Finally, the technology is simply cool - if you are into that sort of thing.
Cons
Lately, the company scaled down on stock grants, but it really did not accompany that with some sort of adjustment of the total compensation package to persist how equitable the employees are.