The verdict
This one depends on what you sell, so there is no single winner.
If you are a B2B company with lead volume, a CRM such as Salesforce or Dynamics and someone who will own the platform, I'd pick Marketo Engage. It is built for scoring, routing and attribution that sales trusts.
If you run an online store of any size short of enterprise, I'd pick Omnisend. It starts free, migration is free and the flows work from day one.
A small B2B team without a CRM link or a marketing operations person should look at neither. Marketo is more platform than you need, and Omnisend is aimed at shops. HubSpot or ActiveCampaign are the lighter options.