I've tried it myself and it's a major improvement however if it would be even better some firewall developing software firms might sue Microsoft.
Now it is viewed as targeting those people who wouldn't have used a firewall if Windows Firewall would not be there. But I don't think it is meant for competing with ZoneAlarm or the others.
Is whole anti-trust issue is really a problem, as it basically forces Microsoft to make some inferior products (this way Windows Firewall isn't seen as a competitor so software makers that make personal firewall don't loose clients) only to evade the legal
Windows Firewall is a Firewall while ZoneAlarm Pro is a suite. I doubt Microsoft can't be sued over Windows Firewall because third parties are moving into suites. I intend on using Windows Firewall and ZoneAlarm Pro (with Firewall capabilities off) alongside
By the way, does anyone know why pings aren't blocked by Windows Firewall in SP2 RC1 even when Allow pings is unchecked?