How DARE you guys have an auto discussion and not invite me!! Time to set the record straight.
An auto is quicker but a manual is faster. As an example, we will use a C4 corvette with 300hp at the motor. Lets give it a 3.45 gear and a T56 transmission on stock tires. You run a best all day pass of 13.5 @ 105. OK, pretty good time! Now, take the manual trans out, put in a 4L60E automatic, stock converter, no shift kit, and run it. You will get a 13.3 @ 100. Notice the ET dropped but so did the MPH. Why? The auto does not put as much power down as the manual, so its slower. BUT, it is able to apply full throttle on the launch and utilize all available traction from the get go. No riding a clutch, no modulation, just floor and go!
From a roll though, the auto will lose to a manual, no doubt about it. But as you guys state, this is a debate on whether an auto is quicker than a manual and yes, it is. Not to mention, it can do it all day, every day, and never whimper.
Now contemplate this. Put a new clutch and slicks in your manual, any clutch you want, and hell, launch it on the rev limiter. You get maybe a 1.8 short time? OK, now take the auto, put in a shift kit and a 4400 Thruster Pro converter and your pulling a 1.6 short time. SAME MOTOR, SAME REAR GEAR, SAME 300HP!!!! For those that want to dispute how a converter works, I can type all day to explain that one. But for now, its a PROVEN fact that in V8 street cars (cuz somebody will bring up Pro Stocks), a manual is NOT and CAN NOT be quicker than an auto.