Pros
If you can stick it out, you can truly do some good. The customers are amazing if you can get passed their frustration with the product. Legacy products with significant market share.
Cons
I was on the customer support team of a company that got acquired. They moved us to their support model but didn’t plan the cut over to their systems at all so our clients were just locked out of getting help for weeks, and our internal help resources acted like we were being unreasonable when asking someone to fix it. The CEO came to town once and had a townhall with just our small acquired team. He proceeded to interrupt, belittle or straight up ignore every woman in the room. I wish I was kidding but it was so obvious that it got super awkward and everyone just sat in silence. My new manager after the acquisition clearly hated his job. I asked him if he was working on anything exciting because I wanted to advance in the company and he just looked at me like I was crazy. Once when I got a raise, he told me not to discuss it because “obviously that’s not legal”. Which I’ll never forget him saying. I was relatively young at the time so I guess he thought that would work on me. When I finally left, after 90% of the rest of the acquired team, my manager told me there was no way I could handle the commute or responsibility of the job I was moving into, even though he was pressuring me to take on more responsibilities a week early. The exit interview was also just shaming me for being one of many to leave the team. In general they don’t really seem to care about taking care of clients or doing much more than maintaining you as a cog in the machine. They are not afraid to use and manipulate you if you happen to be junior in your career. It’s probably a fine place to be mid-career if you're not a woman, want to coast and make mediocre money but if you’re early in your career, please don’t believe this is what work should be.