Pros
None. Some of the companies acquired by ACI had good teams and good cultures. Some employees who experienced the cultures of the acquired companies before they were devoured into the ACI conglomerate have good things to say about their time there. But since 2011, ACI has been furiously enforcing its culture and processes on all the start-ups they acquired. There is nothing positive to say about ACI, other than that they have many customers trapped in long-term contracts - and this is the result of the good work done by the companies they acquired, not by ACI itself.
Cons
ACI is a frightening, appalling work environment. Managers and executives frequently lie to employees. Top executives show a sadistic glee in making others uncomfortable. They seem to hiring senior managers who share the same tendencies. When ACI acquires a company, it usually fires or forces-out the talented employees who were responsible for the company's success. You may be slandered among your former team after you leave. As far as the work itself, ACI destroys all creativity and innovation with a ridiculously convoluted Waterfall-based process. You will literally spend months writing spreadsheets describing your intention to work before you embark on a single real task. Your ideas about how to do things better are not welcome - and will almost certainly get you targeted for harassment, defamation, and the next lay-off. ACI will not be good for your career. You will work with outdated technologies, in processes that reflect outdated methodologies, and you will never get honest feedback or a chance to contribute beyond your role in the "process." Stay away.