Malwarebytes Anti-Malware is a surprisingly effective freeware antimalware tool. It's a relatively speedy malware remover, with the quick scan taking about 8 minutes even with other high-resource programs running. The heuristics engine proved on multiple computers during empirical testing that it was capable of determining the difference between false positives and dangerous apps.
The app has some nice features rolled in, too. It supports multiple drive scanning including networked drives, context menu options including a scan-on-demand for individual files, and the FileAssassin option under the More Tools section for removing locked files. The interface is simple, but pleasant-looking and well-organized. Tabs live just below the oversized logo, with few options per tab to keep down the clutter. The installation process was fast enough, but interestingly offered up the well-kept changelog and an instant definition file update.
Do note that the real-time protection is restricted to the paid version, as is the scheduler for updates and scans. Overall, though, Malwarebytes Anti-Malware is a responsive malware remover that does what it should with a minimum of fuss.