Favre actually comes out well compared to the all-time greats for INT percentage of overall passes. He's not the best of course but better than a lot of guys who were never knocked for throwing INT's.
QUARTERBACK: INTERCEPTION PCT.
Arnie Herber: 9.0 (1,175 attempts, 106 INTs)
Bob Waterfield: 7.9% (1,617 attempts, 128 INTs)
Sid Luckman: 7.6% (1,744 attempts, 132 INTs)
George Blanda: 6.9% (4,007 attempts, 277 INTs)
Sammy Baugh: 6.8% (2,995 attempts, 203 INTs)
Bobby Layne: 6.6% (3,700 attempts, 243 INTs)
Norm Van Brocklin: 6.1% (2,895 attempts, 178 INTs)
Joe Namath: 5.8% (3,762 attempts, 220 INTs
Terry Bradshaw: 5.4% (3,901 attempts, 210 INTs)
Otto Graham: 5.1% (2,626 attempts, 135 INTs)
Bob Griese: 5.0% (3,429 attempts, 172 INTs)
Johnny Unitas: 4.9% (5,186 attempts, 253 INTs)
Len Dawson: 4.9% (3,741 attempts, 183 INTs)
Bart Starr: 4.4% (3,149 attempts, 138 INTs)
Sonny Jurgensen: 4.4% (4,262 attempts, 189 INTs)
Dan Fouts: 4.3% (5,604 attempts, 242 INTs)
Fran Tarkenton: 4.1% (6,467 attempts, 266 INTs)
Roger Staubach: 3.7% (2,958 attempts, 109 INTs)
Jim Kelly: 3.7% (4,779 attempts, 175 INTs)
Boomer Esiason: 3.5% (5,205 attempts, 184 INTs)
Warren Moon: 3.4% (6,823 attempts, 233 INTs)
Brett Favre: 3.3% (9,280 attempts, 310 INTs)
John Elway: 3.1 (7,250 attempts, 226 INTs)
Dan Marino: 3.0 (8,358 attempts, 252 INTs)
Troy Aikman: 3.0 (4,715 attempts, 141 INTs)
Current QB's of note...
Peyton Manning: 2.8
Drew Brees: 2.7
Tom Brady: 2.3
Looking at this list, I think there is one glaring problem. Alot of the guys on this list above Favre played all if not a good portion of their games before 1978. (Other than Kelly, Esiason and Moon) Taking that into account and looking at his actual contemporaries, isn't 3.3% pretty high?