iThemes announced today that both their free iThemes Security and their commercial iThemes Security Pro plugins are integrating Sucuri's malware scanning service.
The free one is just an opt-in one off option, which is nice but can also be accomplished other ways. But the pro version allows for automated scheduling of scans, with notifications to the site administrator if an issue comes up.
iThemes Security has been a successful product for iThemes, and I'm sure their pro customers will welcome the added service. iThemes is including this feature in their top tier of security features, along with two-factor auth and strong password enforcement (which WordPress now handles a lot better too). Their whole suite of features is pretty impressive now, and with a 600k+ free user base they have a lot of folks to market it to.