The Gravis GamePad Pro is the successor to the well-known Gravis Gamepad, and shares many of its useful characteristics. There are both USB and gameport versions; this writeup will concentrate on the USB version as it is the one I have.
Where the original Gamepad strongly resembled an SNES controller, the GamePad Pro looks very much like the original (non-Dual Shock) Playstation controller. As such, it has a D-pad, four coloured face buttons, two shoulder buttons on each side, and Start and Select buttons in the very middle of the controller. As with its predecessor, the D-pad is set up with a screw-on 2cm 'stick' which doesn't seem especially useful.
The buttons feel comfortable, but the D-pad is a circular design unlike the usual plus-shaped D-pads on console controllers which feels a little cheap and uncomfortable. On mine, at least, the D-pad is also a little overly touchy, sometimes sending diagonals when it feels like it's in a straight direction. The construction of the gamepad feels a a little flimsier than the Dual Shock controller, but since the Dual Shock is the toughest game controler I've ever owned this isn't a major problem.
Since it operates as an ordinary USB HID joystick, it worked flawlessly out of the box on Linux, and presumably also on Windows and Macintosh. Compared to the original Gamepad, the advantages of the GamePad Pro USB are the additional shoulder buttons and the more ergonomic 'grip' design, as well as the hassle-free USB interface. Its main disadvantage is the removal of the left hand-right hand switch present on the original, although due to its asymmetrical shape it would be useless to reverse the pad as with the original.
All in all, a reasonable PC gamepad for $30CDN, especially for use with emulators or under alternative OSs where more elabourate controllers may not work.
TheBooBooKitty says re Gravis GamePad Pro: Might want to make a note that this controller IS NOT suitable for hacking as an interface for custom game controls, the directionals block and ghost if you try (the joy PCB is very sensitive to voltages).
This writeup is copyright 2003 by me and is released under the Creative Commons Attribution-NoDerivs-NonCommercial licence. Details can be found at http://creativecommons.org/licenses/by-nd-nc/2.5/ .