I'd like to order a big steaming cup of "they are both pretty bad."
Zappe's 30 yard TD to Meyers was a terribly thrown ball. Meyers was wide open and Zappe all but missed him. It required a sensational adjustment by Meyers when it should have been an easy "catch and walk in." His deep ball to Parker was very well thrown, but so was Mac's incompletion off Thornton's fingertips - and Mac's throw was rushed under pressure and sill almost perfectly placed. Zappe's third deep ball, to Thornton, was also badly missed.
Where Zappe has a slight edge on Mac is that he has yet to just chuck one up for grabs, which Mac did once again (unless Mac can simply not read a defense, he has developed a disturbing tendency of throwing ultra risky passes into the teeth of the defense). On the other hand, the Pats turned one over because Zappe was unable to execute a handoff, and he's had
3 4 passes batted at the line, one of which was picked.
The best thing that can be said for either of them is that the whole Patriots team played like a steaming pile of crap in all three phases of the game and that makes it hard for a QB to play well.