Short version: assuming you’re looking to automate your marketing (B2C or B2B) you can do that with either of these platforms, no doubt.
But it’s a mistake to think Salesforce Marketing Cloud is more a part of Salesforce, than Marketo is. It’s not.
How Salesforce Marketing Cloud fits into the Salesforce.com platform
You see, there’s the centralplatform. This started as the CRM we all know (and, to a degree, love – or hate!) and now contains additional elements such as Service Cloud and Community Cloud.
The Marketing Cloud is, however, NOT built on the central Salesforce system. The core of Salesforce Marketing Cloud (SFMC from here on out) is a platform called ExactTarget. ExactTarget was acquired by Salesforce in 2015 – after ExactTarget, in turn, acquired Pardot (as to make the purchase interesting enough for Salesforce).
Salesforce has added social tools (also acquisitions) to this platform and now sell that as the “Marketing Cloud”. However, ExactTarget integrates with Salesforce just like any other third-party system: through its API.
Therefore, there is absolutely no inherent value over choosing SFMC over Marketo – unless you happen the like the platform better, or perhaps because it suits your needs more.
Is Salesforce Marketing Cloud becoming better integrated?
“But isn’t Salesforce integrating its systems more tightly vs competitors?” you might ask. Of course they are. But the systems are still separate systems. Not to mention that the other vendors (such as Marketo) also ensure their integration with the world’s #1 CRM is as seamless as it can be.
Perhaps one day Salesforce will stop integrating with third-party marketing automation platforms – but considering that would cost them a lot of current customers, I doubt that’ll ever happen.
Pick the marketing automation platform you like and be safe in the knowledge it integrates just as well with Salesforce as the Salesforce marketing products!
I first answered this question on Quora: