So you consider Manning a choker also?
The difference is that Manning actually makes plays. He throws incredibly accurate passes into tight windows, and he has the guts to actually fling it when he needs to get the job done.
Brady's entire game is based on screens and other short passes. The only time he can ever throw deep successfully is when the line gives him all day to throw and/or had all-world Randy Moss out there hauling in anything in his vicinity. He is praised for not throwing INTs but the only reason his numbers there are low is because he doesn't make the plays to get the job done when he needs to do it. If a guy isn't close to wide open, Brady isn't accurate enough to hit him and often won't even try.
And don't even give me Brady's completion percentage stats that are inflated from all the screens and short crap he throws, which are far more than anyone else. If Manning threw as much short easy-to-complete crap as Brady, he'd probably hit 75 percent.