Eloqua, Hubspot, and Silverpop.
At the time, Eloqua had just moved from Eloqua 9 to 10, which was a major re-write, and they were not yet up to feature parity with the previous version. We did not feel that it was wise to take a risk with a brand new version of the product. Additionally, integration to Salesforce, although certainly possible, was not out-of-the-box as it was with Marketo.
Hubspot, at the time, was somewhat light on marketing automation functionality and was more focused on social media marketing and CMS. Their CRM integration capabilities were not strong, and their lead management capabilities were simply not robust enough.
Silverpop were also in the midst of a transition. They were known as more of a B2C marketing automation solution and had recently acquired a small B2B vendor called Vtrenz. We were concerned about product integration issues and decided there was too much risk. However, they did have some great features. For example Silverpop had a great feature that automatically figured out the best time to send an email to a specific individual to ensure click-through.
Marketo aggressively discounted, and I trusted the brand due to excellent content marketing from the Marketo marketing department. I was burned a little by focusing too much on the marketing and not enough on the actual product experience.