Pardot is being used for B2B communications by the marketing department - utilising dynamic lists, landing pages, form handlers, drip campaigns etc.
It was brought in as a more integrated solution when compared to Wired Marketing. The lesson here is that not all products that claim to integrate with Salesforce actually integrate to a high standard.
The Pardot Connector can suffer from some issues when working with Salesforce. Part of this is Salesforce's poor conflict management. Often, users are finding that the Connector has visited a record they are editing, and that they have to re-key all their changes again.
Your data is a huge factor here. If you have a highly fragmented set of records, multiple duplicates, Pardot will have a good stab at trying to tie things together but fundamentally you can find inconsistent results in terms of matching updates to records.
Pardot doesn't like duplicate management tools, ironically considering the above. If it finds the Salesforce record that it is attached to deleted as part of merging, it does not attempt to re-link its own record to the newly formed one.
Because of our poor poor data, we are having negative experiences. I am reluctant to list them here as they should not reflect on what Pardot offers. This is, perhaps, a question to be revisited in a few years time. Just take it as a cautionary tale in org healthcare.
It integrated poorly with Salesforce. While it exists in your org, it created its own network of objects in order to work. These often duplicated the function of standard objects and actually ended up reducing efficiency and streamlining of processes.
It is great if you are a B2B business looking to get a well-integrated piece of software for your org. If you have a problematic data universe and are expecting it to magically make things better, you may find that you're just throwing another piece of software into your ecosystem to under-deliver. Get your org in order before you try to build on top of it.