Most of the companies on this list have as their primary role 'making peoples lives better' directly.
In engineering we tend to be indirect, we rarely meet our end customers, and so rarely see for ourselves the positive benefit of what we do. The only feedback that typically filters through many company systems are the complaints.
Study after study shows that this feeling that your work is benefiting someone is hugely important in achieving job satisfaction. (I don't think I'm uncommon in getting far more satisfaction out of the voluntary work I do outside of my day job, even though a lot of it is just as tough - and unpaid!)
If engineering companies want to make this list I suggest they break down some of the barriers between the end user and the backroom.
Andy Millar CEng MIET CMgr MCMIhttp://www.linkedin.com/in/millarandy
"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert