Pros
Let's be fair, HP is a BIG corporation and has many divisions and locations. I can only represent the pros from my own experience and perspective - which is from the west coast of the US and working on the side of the business that delivered Printers and PCs... this part became HP, Inc. in the recent split. The other half, Hewlett-Packard Inc is the side Meg kept under her wing and is a lot more of what EDS did with the systems and IT solutions; and I didn't have any experience with that business. For me the biggest PRO by far is the people you work with. HP is filled with creative, smart, funny, and caring people that you will work side-by-side for long hours in stressful situations and you will form trust and relationships. It is amazing to have been part of several teams that delivered product and services to the market, despite some pretty tough internal organizations struggles.
Cons
HP, Inc. (or Hewlett-Packard as they formerly were known) has a long, rich history in both innovation of technology but also in management and leadership practices. Yet sadly in most aspects, both of these are just that... history. The current day HP has been poorly directed from the CEO for over a decade. You get what you focus on to measure - and at HP what is being measured at the individual contributor level is not truly a reflection of the individual's values or skills, but simply a by-product of poor senior management decisions that get paid for by the people doing the actual work. But HP is big... and now there are two of them. So it would seem that in some divisions and some teams there would still be great jobs and environments. Sadly from my experiences, these are not the "norm" any longer at what once was a great company to work with.