Frustrated with Marketo/Segment Sync Issues

We currently are using Segment to track data from website and customer activities within the product (SaaS). This data syncs with Salesforce and then Salesforce syncs with Marketo. The issue we are having is that we can't seem to get the Segment-Marketo sync working and thus the SFDC workaround. We are also no longer using Marketo forms on our site. Anyone else have experience using Segment and Marketo with any level of success? We have vast amounts of incredibly valuable data we want to leverage to create a personalized email experience but can't access it via Marketo and are thinking of making a switch if necessary.