Pros
Avaya offers competative compensation, flexible working arrangements (in particular, work at home is warmly supported), and good work family life balance.
Kontras
Avaya is attempting to transition from a first generation technology company (a hardware maker) to a 3rd generation company (software as a service). Based on what I've seen, this transition will not be successful. Avaya has a long history of buying small technology companies and integrating their products (with more or less success) rather than building things in-house. For software development in the US, Avaya is a losing proposition. Development (and some other activities, like technical writing) are being moved offshore. The strong culture of work-at-home or remote work makes networking with coworkers and working collaboratively very hard.