Pros
Rather than plucking people from other companies, Nielsen has a strategy of filling positions from within which gives a great deal of career and growth potential. On the whole, the company is quite flexible - if you decide your skill set isn't suited for the area you are in, you can request to be transferred to a different group, different business unit, etc. The company is also quite flexible if you need to work from home or leave early on a regular basis.
Cons
Having recently been purchased by a private company Nielsen has transitioned from a "people first" attitude to a "profit first". Not a bad attitude when running a business, but it is nearly a 180 from the original culture of the company. The result is that there are many people in leadership roles who aren't consistent with the current message creating conflicting directives at all levels within the company. Low morale tends to quickly follow suit as employees cannot keep up with the ever changing landscape.