I used Hootsuite at my previous job and it's awesome! Things I liked about it best,
1) you can monitor what's going on in all of your accounts in a single view, and manage them all at the same time. It saves lots of time when you have over 10 channels and need to quickly manage content & reply to feedback
2) it allows you to schedule messages in advance and shows them in a calendar, so you don't need any spreadsheets for your SMM plans
3) its interface is super handy, much better than the native interface of any social media in fact.
However, I can't tell anything about Marketo-Hootsuite integration as we had no reason to use it at that time.