Eset Smart Security 4 ($60 for one year, one PC; $70 for one year, three PCs, as of 12/2/2010) came at or near the back of the pack in most of our malware detection, blocking, and disinfecting tests.

It fully blocked 21 of 25 real-world attacks (a good result, but not outstanding among the products we looked at in this bunch), but it stopped an appalling 89.2 percent of known malware--significantly lower than top- and even average-performing products in this roundupEset's 60 percent success rate at removing active malware also tied it for last place among its peers. And it tied for leaving more inert malware remnants behind than any other suite.

On the plus side, at least Eset is fast: At on-demand scanning it was the quickest scanner in our roundup, and it scored a solid second place in on-access scans that run when a file is opened or saved, too. System performance was barely impacted with Eset installed; its rating was good enough for third place among the 13 apps we reviewed. As well, Eset keeps the false positives to a bare minimum.

That's cold comfort considering some of Eset's serious drawbacks. Its download and installation process was the most aggravating of all the apps we've reviewed, an exercise in frustration as you're required to register and enter Eset-provided user names and passwords again and again.

Once you do get Eset up and running, everything looks like it's going to be easy: The home screen is simplified to a fault, with just a handful of options available to the user. But should you find the need to dig into the settings, all of that changes. Under the hood, Eset is a virtual rat's nest, with an exhaustive tree of option after option that even experts will find off-putting and convoluted. And, you likely will have to venture into this no man's land in relatively short order: Eset does not give you an option for a complete system scan on the home screen at all. You have to configure it via a badly labeled ("Selected profile") drop-down menu found only on the options screen.

Eset's claims of having two home screens, one for experts and one for beginners, are also misleading: If you toggle the system from "Standard mode" to "Advanced mode," the only difference is the addition of a single new option on the taskbar: "Tools," which lets you look at log files, the quarantine list, etc.

Eset Smart Security 4 features such a rare combination of poor security and a baffling settings system that it's impossible to recommend, no matter how fast it is.