like johnwill is saying, any hardware firewall is going to be no better than a router.
for a firewall to be truley effective, and not cause you issues, it would need to be running on the pc you are using, that way you can interface with it and tell it things are ok or not.
and like johnwill was saying about a router being good enough, it can be for some people. it would for most of the people i know, but some of them have a habit of installing everything and anything they find online (i'm in that group myself), so that's where a software firewall prevails, seeing the outgoing activity, and asking you if it's ok. it might be a keylogger. a hardware firewall, regardless of quality, can not do this.
because of that, a hardware firewall has to be set to either block it, or allow it, or allow some, which requires tons of fiddling.