Brian, I'm curious about their request for integration with Marketo. I've worked with Lead Forensics before and are currently looking at their solution for my current company, but to my knowledge there is no Marketo integration. If anything, we were looking at a custom API integration that we would build in-house. The only integration they have right now is a push into SFDC, but even then email address is not yet part of that integration (leads are created without email). I was told pushing email is on their roadmap.
I have had success with them in the past, they apparently have a higher enterprise reach than their competition and I can say that their UI/UX is a lot friendlier than their competition as well.