Pros
There are many reasons. The atmosphere at TI is extremely conducive to work. Strict hours are not enforced; you have plenty of leeway to restructure your work around personal life as long as you get the job done. I enjoy excellent relationships with my peers and my managers, and I get great feedback both when I do well and when there are areas where I need improvement. TI is also fairly good at rewarding people who make significant contributions to the organization's success. Other reasons? Great job security (I've been here for well over four years and many of the people I work with are the same people I met here when I first started) and stability, great benefits (including educational assistance), an employee stock purchase program (great savings tool!), and a perfect vacation/time bank system. But above all, as an engineer TI has given me an environment where I can do what I do best and enjoy doing it. I love working here and probably wouldn't move to another company even if they paid more.
Cons
There aren't many downsides, but I'll try to list a few. First there's the "cube farm" - lots and lots of cubicles. Then, being in the semiconductor industry, your career choices are somewhat limited should you choose to change jobs. A lot of what you learn to do at TI is very proprietary -- in essence, choosing a career at TI is a long-term investment. Also as a product engineer, unless you prove yourself to be innovative and stand out from the pack, you could find your work quite monotonous as you end up doing the same type of things over and over again. Working here can also be quite stressful at times, especially if you're in an organization that deals with quality. Deadlines and customer commitments could mean very long hours and tedious work for stretches. You need to be able to work well independently or you could struggle.