What is that delay between a tap and cursor movement?
In essence, this is due to poor drivers in Windows. The Mac drivers have been created better than those in Windows.



The problem is created because the trackpad is waiting for the possible second tap to indicate a double-click. In OS X, the drivers are simply 'smarter' and understand better when you intend to double click or click and move.

Indeed, actually clicking the trackpad then moving is instantaneous since the physical difference between a click and the cursor movement means that it can distinguish between a double-click and a click and move much faster since it doesn't have to wait for that second click.

Such behaviour can be noticed if you put an old iPhone without multitasking next to an iPhone with multitasking, and press the home button on both. You should notice that even though the newer iPhone should be quicker, it's not. The older iPhone reacts quicker, since it doesn't care if the home button was pressed twice - the same action is carried out. Conversely, the newer iPhone must wait those extra few milliseconds to see if you press the home button a second time, indicating that you want something other than the app to close (you want the multitasking bar).

With careful timing, it is possible to notice a similar yet opposite effect in OS X to the one apparent in Windows. Whilst a tap-move in Windows causes the cursor to lag as you noticed, and the same behaviour in OS X doesn't cause any lag (the cursor moves immediately), you may notice that a tap-move-tap in OS X causes the cursor to 'snap' back to its original position (if the 'move' was small enough) since it predicts that you wanted to do a double-tap on the same spot. In Windows, a similar tap-move-tap is equally predicted as a double-tap, and to make you do this in the same spot, it prevents you from doing the 'move' for a split second. Two different methods for overcoming the same problem, yet one is considerably better than the other!

Whilst I haven't tried it, Trackpad++ seems like something that should fix it by replacing the Boot Camp drivers with "much better ones"…