Editor's note: This review includes updates and revisions filed on 5/28/09.

Panda Internet Security 2009 boasts an extensive feature set and an easy-to-use interface, both of which helped it attain a fourth-place finish in our midyear security suites chart and our roundup of eight security suites. It finished third in "Paying for Protection," our initial 2009 roundup of such suites. But its ability to block malicious software didn't rank as well, and the suite had some genuine difficulty dealing with some especially nasty malware, despite its new Internet-based scanning feature.

At $60 for one license and $80 for three licenses (prices as of 5/24/09), Panda's suite runs a little high relative to many competitors. It successfully detected about 97.8 of the Trojan horses, bots, password stealers, and other malware in AV-Test.org's library (98.1 percent excluding adware). This compares with a 93.6 percent detection rate in our previous testing (94.8 percent excluding adware). Panda ranked fourth out of the group of eight evaluated suites (for which detection rates ranged from approximately 57 percent to over 99 percent). But it ranked only sixth for its 36.46 percent detection rate in heuristic tests that use 2-week-old signature files to simulate how well security programs can catch new, unknown malware.

Panda's suite caught over 95 percent of spyware designed to steal passwords and financial information.This is a marked improvement over our previous testing, when Panda caught just 69 percent of those particularly harmful varieties. In behavioral detection testing it, caught 9 out of 15 malware samples based on how that malware acted on a test PC, but that placed it only sixth in that category.

A new Internet-based addition to the 2009 version called Collective Intelligence sends a hash, or signature, of a to-be-scanned file, along with information about its behavior, to Panda servers. By comparing the signature against a large online database of signatures, Collective Intelligence attempts to bolster the scanning abilities of the program on your PC and speed the suite's ability to detect new malware.

Panda's package clocked in with the best on-access scanning speed, which tests how long it takes to scan files as your PC opens or accesses them (though it proved the slowest suite for scans kicked off manually or according to a schedule).

It covers all the bases for expected features and adds a few extras, with parental controls, backups, antispam, and antiphishing. The suite also includes a useful vulnerability scanner that can check for patches missing from your PC. Though some of the extra features could use more polish, Panda's application was the only suite we tested that offered all of them. The vulnerability scanner, for one, is a welcome extra, since practicing good PC safety means making sure your computer is up-to-date with patches. But you'll need to launch the scan manually (you can't schedule it), and the overall security-status report won't change even if you're missing a critical patch.

To use its parental-control feature, you'll need to create a log-in and password for each person using the computer. Each log-in has its own profile that defines site restrictions. Then, when anyone starts up a Web browser, the user is prompted to select a parental-control log-in and enter a password--distinct from any that might be necessary for the Windows account--in a pop-up.

Panda's backup feature can back up by file type (such as photos, Office documents, or Internet favorites) or by selected folders or drives. It's relatively easy to set up, but you can schedule a daily backup only to another hard drive or to a CD or DVD. Its antispam option adds a toolbar and spam folder to Outlook and Outlook Express.

Panda's offering has a good interface and provides the fastest on-access scan speed of the suites we tested in this roundup, but its good--though middle-of-the-pack--malware detection prevents it from being a top pick.