The cost of Marketo is relatively high, but the features justify the cost. As long as our programs require tracking on lead gen, etc, the product will be renewed. Marketo has had spotty support in the past, but overall, the support is improving. The documentation is also getting better, but is lacking in some areas.
Ensure that the cost is justified by how you will use Marketo. There are other products in the space that do more, and more efficiently, but the key is matching your desired marketing results with the features that Marketo provides. Ensure that the SLA meets your expectations and that you have an onbording plan with Marketo that involves your entire team - anyone who will have access to the system and ensure that those in your organization know how to truly use the tool to the best advantage to meet your goals.