If you're looking for a connector that interacts well with Marketo, by ALL means, avoid SugarCRM. It has been nothing short of a nightmare with our instance and the connector is poorly supported, if at all. Steer clear.
Dan Banning - we integrated our Dynamics CRM with Marketo, so if you're researching this system at all, I'm happy to chat. I've never worked with Salesforce, so I can't weigh in on popular opinion.
Marketo seems to offer some additional functionalities with a SFDC system, but it's nothing that I can't find a workaround. I've been appointed the CRM system admin, and as a person with zero technical abilities, Dynamics is really easy to customize.
I echo everyone's statement above on figuring out what your requirements are for the system: additional integrations, workflows, and licensing costs. Happy to bounce any ideas off you if you want a second pair of eyes and ears!
I agree with above responses. I would personally lean towards Salesforce. If you are looking for something more than a CRM considering their breadth of offerings(listed few below) that caters to different business needs, they might offer a better price. Our company always had a better customer experience with Salesforce and they offer better support services.
Multi-org strategy if you are multi-product company
SFDC is the most widely-used with Marketo. It's got the most documentation, and most Marketo experts have experience with SFDC. And there are a lot more SFDC Admins than any other platform. So with SFDC you'll have the widest pool of experienced people to run your Marketo, run your CRM, and ask questions of in the general community.
I have had mixed experience with Dynamics 365 integration. Intermittent and unexplained sync failures through their native connector resulting in Contact inserts initiated in CRM not syncing across. Similar sync issues with other custom entities. I understand Marketo is built on the Salesforce platform so I expect their connectors may be more reliable with Salesforce integrations. Though I have no direct experience of this myself
No, Marketo is not built on Salesforce platform
At the origin of Marketo, many former SFDC employees joined Marketo, though.
We have experience with both SFDC and MSD connectors. SFDC one is richer on a functional standpoint. we tend to have a little more frequent issues with MSD connections too, but I am not sure that would be significant on a rigorous statistical standpoint.