Pros
You will be working with some of the best people in the trade. Qualcomm has been carving a stronger and stronger market position for itself. This makes the company comfortable in taking risks (nor all of which pay off) - hence innovations is highly prized (second only to execution) Compensation is good. The company adjusts to any changes in the external marketplace readily and quickly. This means that it shall not be the "most' you can get - but you will be very close - and hopefully the other intangibles will more than make up for any difference. People at Qualcomm are very helpful and collaborative. Team spirit is present everywhere. Generally speaking everyone is competent and many are arguably the best in the business.
Cons
With a few exceptions, Qualcomm does not make end products directly. It must read the minds of large cell phone makers, network providers etc. There is always a difference that must be compensated when shipping the product. So, in several teams - especially which work on customer facing roles, life shall be very busy - and even chaotic - with a lot of pressure. If there is factory that has stopped making phones - or a phone's launch is at stake - all because of a bug you are working on, the pressure (and visibility) can be intense.