I'm looking for the best all around joystick.  The magically elusive "everygame" stick.  Well with the Happ 49way, GP Wiz 49 encoder, and floyds rotary adapter, I am almost there.  If I could only incorporate a topfire in there, I would have everything.
I agree that a triggerfire would be better for accurate rapid fire shooting and more ergonomic for button presses than a topfire.  My problem with the triggergrip s that, I cant also play other games with it.  I wont want to play Donkey Kong with a big ol trigger grip, nor will I want to throw fireballs in Street Fighter II with a Tron Style trigger grip.  But I could do all this stuff with a topfire.  And if I wanted to play tron, the topfire would work pretty nice.  my $0.02.