Hardware ones are much stronger, reliable,
True
protect from a wider range of threats,
Depends on the sofware fw you compare it too and who's doing the configuring.
and are very cheap.
Yes
A superb SMC Barricade
Those are pretty sweet for a home user

Of course, if you want to control outbound traffic to a high degree you need a software firewall or some kind of sandbox application.
I personally prefer to use both hw & sw firewall. Must be my paranoid stricken personality...