Pros
Flexible schedule, no pressure from collegues or superiors. Can easily get away with working at least one day per week from home, as well as leaving early or coming in late often. Casual atmosphere. Most of the engineers are intelligent and competent enough. Pay is average, but you can get away with working ~30 hours per week so if you're not overly ambitious, pay is pretty good. Health insurance package is decent.
Cons
Company/industry is extremely vulnerable to weak demand in the semi-conductor sector. Read massive layoffs during recessions. Teradyne customers only buy Teradyne products if they are experiencing growing demand, or if they have a new product for which they require new testers. If demand for the products of Teradyne customers is flat (not even a recession, just flat), Teradyne will sell little or nothing, meaning during a poor economy, huge layoffs occur. During the tech bust 2001-2003, over half the company was laid off; during the 2008-2009 recession, another 60% of engineers were laid off. In 2000, company employed 12000, now it employs 3000, if that. If you see a recession beginning, start looking for a new job. Even if you are not cut, most of your friends will be, and your salary will also be cut by at least 10%, with no hope of a raise for years at some points.