NFL.com's preseason pass was great.
I did not get to see the live coverage, but the on-demand replays are awesome. If you have the bandwidth, you can get HD, if not you can turn the quality down for a smoother connection. You also have the option of selecting between the home and away broadcasts.
I think it is well worth my $20.00 for the preseason games, and $50.00 for on-demand regular season games, since I am currently living out west and working weekends.
The only downside is that games in local markets are blacked out for 24 hours.