Pros
Great employees (peers only). They are smart and a joy to work with. Competitive salary (usually). If Avaya could fix management it would own the market, as the technical prowess is already there. Might even be tolerable if you get a boss who is not a robot. They're rare but they exist. Good news is if you hate your boss just wait 2 years for the next reorg.
Cons
Senior management is poor. Too much middle management with no power to effect change.. No business process is too onerous to redesign and make worse: from business travel booking to expense reports to yearly reviews, each year the process gets more convoluted. "yes men" managers/drones get promotion. Identified problems that are recognized rarely get solved. Blind devotion to outsourcing to India for engineering and Brazil for pro services hurting quality. Siloing of engineering is very bad. They stonewall and insult other employees rather than fix bugs. Avaya is a company of chiefdoms. If you stay at Avaya long enough, you'll see that management just alternate strategies every few years. First we're partner centric, then channel centric, now it's partners again. Repeat forever... What's old is new again, it's just like fashon. After a while you roll your eyes and ignore it and get on with your work. Avaya has also set about being cheap: home office expenses are no longer paid (broadband, phone line). They give you a crappy VPN phone that frequently reboots mid-call. Of course the phone works on broadband that you must pay for yourself. So you pay for your home office expenses (heating, electricity, Internet) and a multi billion dollar corp gets a free ride.