Personal remarks:
avast: does not disable Windows firewall by default. Scheduling is complicated to common users. Misses parental control (present in other suites).
AVG: gadget for Windows 7/Vista. They "sell" the separation of antivirus and antispyware, link scanner (web site rating) and identity protection. Should avast learn from one of the most downloaded antivirus round?
Avira: they continue to release the heuristic level on setup (games, jokes...). avast releases heuristic level without further info (high, normal, low, off) and not at setup, but further. It misses the "repair" installation option.
BitDefender: has a pre-install scanning, three different interfaces (basic, intermediate, expert). Does not have a non-install option for the shields (only disable them). Allows searching the help file through the interface (not only shown, but search).
eSafe: good artistic icons (not easy to understand what they mean). Does not have "repair" or individual removing of any part of the suite.
ESET: installation process is not clear, updates are applied after the setup finishes (good!), simple/advanced interface that can be switched. Like AVG, shows antivirus + antispyware. There is a repair and a non-obvious component removal option (for firewall and antispam).
F-Secure: unified setup file (antivirus and/or firewall). Setup only in English. Very limited options for component installation. Setup also updates the virus definitions at the end of the process (avast! should learn...). Misses a "fix" button. All statistics in one page. No "repair" option. No components uninstall.
G-Data: like avast!, allows non-installation of some features. There is a CPU graphic about its own use. Does not allow components uninstall (change installation).
K7: good detection rates, confuse installation process (bugs), does not automatically disable Windows firewall, weird (?) color scheme interface, misses a "fix" button. No repair and no components uninstall options.
Kaspersky: too many false positives. There is a safe mode run: sandboxing suspicious applications. A virtual keyboard. There are no installation options. Scheduling scans is complicated. There is a (no-intuitive) Windows 7/Vista gadget. No selective removal of components.
Kingsoft: installs a device driver for the network service, misses an unified interface for the components (antivirus, antispyware and firewall). Very confuse uninstall procedure. English-only interface.
McAfee: high number of false positives, very flexible custom installation, virus definitions are downloaded after the setup. Gives sites ratings at search pages. Does not allow repair or single component uninstallation.
MSE: antivirus-only (not suite). There is no custom installation. Automatic scan (and update) after installing. Very few options to configurate. No way to repair installation.
Norman: custom installation allowed, updates invoke UAC, allows repair and componentes install/uninstall. Easy interface (although not easy scheduling and licensing).
Panda: custom installation, weird wizard for updating, no web ratings, no repair, no custom uninstall. I can't understand the "backup" features.
PC Tools: no custom setup, automatic quick scan after setup, misses a "fix" button, has safety ratings for webpages into searches, no repair, no selective uninstall.
Sophos: designed for business network, with a HIPS. Like avast, there are navigation buttons on the interface. Difficult to be used in netbooks. Multiply items on Control Panel to uninstall. No repair option.
Symantec: no components intallation setup available, interface as vertical list of components (too much information), map area without much utility, reenable components automatically start critical scan (good precaution). Smart Definitions download only the most relevant/recent definitions (not clear to me). Webpages ratings available. No repair. No custom uninstall.
Trend Micro: no options setup, smallest interface, parental controls available. No website ratings. No repair, no components uninstall.
TrustPort: very little options for install, misses a "fix all" button, setting scannings are complicated, no search result ranking facility. All-or-nothing uninstallation. No repair.