Vantaggi
For the most part, the people are really great and make working at Dell very enjoyable. Work/life balance is supported by most managers and, as long as you get your work done, you can pretty much come and go as you please (within reason of course). In addition, since Dell is such a large company with a global presence, there is a wide range of departments, jobs, and locations, so you have opportunities to not only interact with lots of different functions and cultures, but also to potentially work in different areas and locales. (Now, whether or not you're actually able to move to another department or location is a completely different story!)
Svantaggi
The expectations tend to be unrealistically high and the pressure to perform beyond those expectations is enormous. Many people suffer from extreme stress and related health problems due to the high demands of the job. It's not unusual to work 60+ hours a week on a regular basis. The environment has become particularly tough since the latest round of layoffs started last year. Many benefits have been reduced or eliminated (like annual bonusses and the employee stock purchase plan) and a standard phrase you hear these days is "If I'm still here... (when the project ends, etc.)". The culture has really changed over the past few years and it's become an increasingly difficult place to work.