Decent product but at a cost
We use fiserv for our core data processing. The platform works OK and has its limitations, but fiserv is actively working to improve it and has an acceptable roadmap in place. I wish it could happen more quickly, but so does everyone else. My biggest issue with fiserv is with billiing. The invoices are very confusing and difficult to know what each charge actually relates to and we often find errors on our invoices and have to work to get them corrected. Our Account Rep is great and always helpful, and we understand we have a duty to know what we are paying, but it can be difficult when the details on the invoice are confusinig. Additionally, and I know this is not unique to fiserv, the costs involved with even minor changes is extremely high. Becuase of this, we often hold off on taking steps that would be helpful but not, by themselves, worth the minimum cost to do anything.
Overall, fiserv is not a bad company and it's not a terrible experience. When the time comes, however, I cannot gurantee that I would commit to staying on with them.