You can install different programs in different partitions that contain an individual OS, as long as you <i>restrict the use of the programs to the partitions associated with those operating systems</i>. In other words, don't install Norton within the partition that contains Win98, and then run the program to scan the partition that contains WinXP. And don't install McAfee within the WinXP partition, and then scan or try to run the program within the partition that contains Win98. Once you've booted up into an OS, only use the tools that have been actively installed into that partition, where the elements of the program are registered. Otherwise, you may be looking at BSODs, data corruption, or an unbootable volume in the future.
Panda not only outperforms Norton in some cases, but when auto-updating the virus definition file <i>and</i> the program's components, is much faster than using Symantec's Live Update, which has always been somewhat buggy, IMHO. The virus definition .sig file can also be downloaded manually from the web site very quickly, if you've got a broadband connection, which is a nice addition.
Panda also has a feature called CPU Load Management, which reduces CPU usage during a scan to prevent other foreground tasks from slowing down.
One of the best aspects about the program is that if a suspicious file is found and quarantined during a heuristic scan, you can send it directly to Panda and have the file tested. This works 24/7, and the response time from the company is par none; I've received answers within five minutes or less, even when mailing them multiple files.
I wish you good luck, if you think that you'll get the same sort of service from a company like Symantec.
Panda also offers free removal and repair tools for the majority of recent, major viruses that are identifed, (without installing the utility), and a free online scan for those without any current protection.
Finally, two other useful features. Panda allows you to create completely customized scans, and also creates an entry in the right-click menu, so you can scan an individual file or folder, even if the program is not currently active, or started when Windows is first loaded. It's very handy to be able to scan a single file in a few seconds, instead of having to scan an entire partition, especially if you have an interest in P2P programs.
Try it for yourself, and make your own comparisons. You can download a free evaluation version of the software.