Pros
Very smart people have been drawn to F5, and for the most part, have stayed. Very best people have jumped ship, and that sort of thing will turn a company's fortunes, no matter how good they USED to be.
Cons
Management seems to have enormous latitude (limited HR oversight) in deciding how to treat employees. If a manager decides he or she doesn't like you, you're toast, and no one can, or perhaps will, intervene on your behalf. Sounds simple, right - just stay on your mgr's good side. Not so fast. It can be anything, even a rumor or unverified innuendo about you that tips the scale toward getting on a "list". I got on such a list because of something others have stated - limited growth opportunity. If you ask for a promotion or even movement within F5, that can (it was for me) enough to turn you into a pariah. And no one will help. I'm leaving after five years because I can't think of anything else to do. And whatever happened to the previously good work/life balance?