Pros
It's not one company. It's like a 1000 companies rolled into 1. It's a great place to learn if you grow from one business unit to another, from one role to another. You cannot run out of things to learn.
Cons
It's luck driven. If you are lucky to have good management, everything is great. If you have the bad luck to report under a bad management - good luck. Pressure is high especially when the external environment is bad - this leads to bad executive managers showing their lack of understanding of the business. Bad decisions then lead to very bad things happening for the business, for the employees, and then finally themselves. HP used to pride itself for paying amongst the leaders, no more. Previous hits like the audio oscillator, calc, hp3000, inkjet, laser, etc... will not drive the company into the future. The recent breakup into HP Inc, HPE, and DXC... not sure if that is smart. The HP way has been flushed down the toilet in recent years, especially in Asia.