Alexandra, we are in the process of rolling out Marketo SEO to all Marketo Lead Management/Dialog customers. With that product, you will be able easily find out what keywords your compeitors are using via our Keyword Suggestions by URL functionality. More info here.
Marketo SEO also provides info about inbound links (how many & the priority/value). The info is provided at the page-level (such as your competitor's home page) rather than at the site-level so that's why I've marked the status as "Already Have It (Partially)". More info here.