The verdict
If you run an online store and want email, SMS and push in one place, pick Omnisend. If you are a B2B team that already runs your sales process in Salesforce, pick Pardot.
For most small teams the choice is easy, because they fit only one of the two. Omnisend is a poor base for long B2B sales cycles, and Pardot is a poor first marketing tool for a small team. It is sold on annual contracts and priced per organisation, and its value comes from the link to the CRM. If you are small and B2B but not on Salesforce, I would look at HubSpot instead. It ties marketing and sales together and is easier to start with.