Has anyone using Marketo switched to SFDC Lightning? If yes, what did it entail? Did you need a new Marketo instance? Did you need to change the Org ID (SFDC URL)?
"switching" to lightning is a matter of clicking a button in your classic UI and using salesforce in a new UI. There's no change or loss to your data or instance or Marketo sync.
The only thing you may need to change is your methods of doing things in Lightning e.g. bulk adding salesforce records to a salesforce campaign.
Hi Nichole - there will not be any changes needed in Marketo. Making the switch will just change your experience in SFDC.
Make sure you are using the latest version of the MSI package in SFDC. Run an upgrade (simply reinstall the package) to make sure.