We are overall very satisfied with the results we are getting with Marketo. They have an intuitive UI. Very flexible platform when it comes to scoring, workflows, and design of landing pages/forms/etc. I would love to see better social integration. However, their sales enablement tools are by far the best compared to competitors.
Our only issue with Marketo is their renewal process is awful. You work with a new rep every time that tries to increase cost by 50%. We negotiated to a great price when we started using Marketo 3 years ago but every renewal year its like starting from scratch.
Marketo has also worked to increase client satisfaction with their service team and things have improved.