Marketo is an all-in-one marketing automation that handles every aspect of the automation process, from capturing leads to turning them into buyers.
Marketo is also one of HubSpot's chief competitors - in terms of features, target audience and market size. While it does lack some of the inbound marketing features of HubSpot, it offers substantially better personalization and engagement capabilities.
In terms of pricing, HubSpot might be cheaper on paper, but if you were to do a feature-by-feature comparison, you'll likely end up paying similar prices for both.
The downside is that Marketo isn't nearly as small business-friendly as HubSpot. If you are an agency or a smaller outfit, it might not be right for you. For others, it's a great HubSpot alternative...Full Marketo Review