Huge difference IMO. Check out the schedule.
2003 New England Patriots Statistics & Players - Pro-Football-Reference.com
By memory my account
Buff-awful
Philly-dominated
Jets - was tight, but Pats pulled away
Skins- awful
Titans - was tight, but Pats pulled away
Giants- was tight, but Pats pulled away
Fins- Tight game all the way.
Browns- Ugly, but Pats lead most of the game
Broncos- Nice comeback.
Cowboys- Pats dominated
Texans- Ugly game. Pats kinda lucky to win.
Colts- Epic. Big blown lead but its the Colts.
Fins- Tight but Pats pulled away
Jags- Pats owned that game.
Jets - Pats owned that game
Bills- Domination
Notice a trend? Except the Colts game they didn't have any crazy blown leads. There were some games that could have gone either way, but thats the NFL.
2003 Pats were 10-0 vs playoff teams. Jets right now are 1-2 vs likely playoff teams.
There is no comparison IMO.