I left a bit over a month ago after nearly 10 years. It took me about a week of transition shock to begin wondering how/why I'd stayed so long. Fiserv WAS the company from which I'd hoped to retire someday, but that company stopped being a few years back. Even so, I stuck it out, as I was able to see the benefits of becoming one Fiserv, and as a former people manager, was passionate about being part of building that.
Thing is, I got so tired of seeing talented, knowledgeable people RIFed within 3 years of their planned retirement. In fact, during my 9 plus years of service, I personally knew of exactly 2 associates who were actually able to work until their planned retirement date. I know dozens who were RIFed because they became upper middle aged. In one's and twos, it's not a problem for Fiserv to "prove" that these associates ages were only circumstantial, but I firmly believe that age discrimination based terminations are rampant there, and that it would take very little diligence to find legal grounds for a class action age discrimination lawsuit.
Word to the wise - if/when you leave, do what I did not do. Take a week or two between employers for some occupational detox. It wasn't apparent to me until a few days into my new role that I'd become pretty badly damaged, and a few good current coworkers (who are also former Fiserv coworkers) had to endure me while I shed the scars of oppression and fear.
I'm here to tell you that leaving is hard, and it was one of the most scary decisions I've made as an adult. I wouldn't go back and change my decision for any amount of money based on what I know, still hear from friends who still work there, and from what I read here.
Best of luck to everyone and Merry Christmas.