I've installed the Firewall, AV and "Verification Engine" on one of my PCs. You have to register and they email the activation codes. Updates are daily, apparently.
Installed easily enough though XP didn't recognise the AV as being installed.
Will post back if there are any other issues but my previous security packages (Norton, Panda, AVG/ZA) never picked up anything so I wouldn't know how to rate the Comodo programs.