Firewall of F-Secure IS

I'd need a Firewall/AV combo for 3 machines running WinXP, Win7, and Win8 (besides linuxes..), and was wondering how's the firewall side of F-Secure (security, ligthness on resources, other considerations).

From F-Secure's site:

I was planning to go with Comodo and Avast free version, but the dough required for F-Secure isn't much and there's the Web Shield issue with Comodo&Avast combo, so I was thinking that perhaps instead of mixing two different vendor's products I'd get F-Secure IS instead. I know their AV side is great, but how about the firewall?
Using Windows' own firewall as a base, especially with WinXP on my mini notebook...
Comodo would seem stronger, or would it?

 

I am using the new F-Secure Internet Security 2013 that integrates with the Windows Firewall. It seems to be working fine. It still has many of the same protections as previous versions. I liked the F-Secure firewall but my guess is that they moved towards this more simplified model in order to coexist better with the Windows firewall to help prevent developmental conflicts with Windows 8 and future updates and releases of Windows. The only thing I found about the newer F-Secure is that while most of the time it's relatively light on resources I have noticed that on my eleven year old Windows XP Pro machine it slows down noticeably more than it did before with the previous version of F-Secure during updates and scheduled scans. This slowdown is especially apparent if the update or scan happens while actively using a browser. Using F-Secure 2013 still provides a performance improvement over most of the other available security suites I have tried. Also it's important to note that on that same machine I also have SAS Pro and MBAM Pro running with their real time engines enabled.