Lik-Sang Boom PSX/N64-USB converterI got this direct from Lik Sang (
www.lik-sang.com) and it worked right out of the box. The price was reasonable (~US$13) and the delivery prompt. I bought it because the Logitech controller I had just wasn't that great a controller and figured I'd do better with the Playstation controllers I remembered from my console days and in fact I'm using a pre-rumble Playstation dual analogue joypad I picked up second-hand from a Gamestation in town.
In actual use the analogue sticks show up as separate analogue sticks (one is X-Y and the other is Z-rotation left/right and Z+/-; the d-pad as separate buttons. Analogue stick buttons also register, but I've never tried using them in-game.
Pros: Can use a mulititude of Playstation and N64 controllers for a modest price. Controllers show up as HID device so you can use the joypad with other games like Lego Star Wars(!).
Cons: Have to connect joypad to converter before connecting it to system or weirdness occurs. Only works with PSOne controllers, but there's another device that's also compatible with PS2 ones. Doesn't work with four-way multitaps (to my knowledge, but again, there's another converter that should do the job).
Logitech Wingman RumblepadThe first controller I bought to use with the Mac. It's wide with tiny buttons and frankly isn't that great a controller. I bought it because it was cheap and advertised Mac compatibility; if I had seen a Dual Action Gamepad I would have got that instead for sure.
The d-pad action doesn't feel very precise and doesn't always register. The button layout is like an Atari Jaguar controller with only two shoulder buttons and six on the face. The shoulder buttons are big and have a good texture to them; the face buttons are little blue chiclets which seem okay at first, but get a dozen games of galaga under your belt and you'll notice that they can start to feel mushy and stick a bit. No Start button; only select and an analogue-digital mode button. The analogue sticks are okay, but have way to much play for my taste and for whatever bizarre reason surrounded by a square outline, which, like the Dual Action Gamepad, means that calibration takes a couple of attempts.
Not even sure if it's for sale any more, but I'd probably avoid -- especially since the rumble feature is useless.
Kensington Optical Expert Mouse (Wireless) This is not cheap (about US$100), but a quality piece of merchandise. The base is slightly inclined and comfortable to use and includes a wrist rest. There are four buttons arranged in four corners around the trackball (so not ideal for Missile Command) and a scroll ring that acts like a scroll wheel on a mouse. The trackball itself is as big as a cue ball and heavy. Really nice action thanks to the optical sensors and the mounting points. There is a wired model, but I got the wireless for future use of computer hooked up to TV. Conversely I need to put in 2xC-cell batteries, however the battery life is excellent and I've only had to replace then once in the past year.
I'd recommend against using the Logitech drivers as the top buttons won't show up as Mouse3 and Mouse4, but whatever limited range of key presses you assign them in the driver menu. Without the Logitech drivers the trackball shows up fine and works great, so why bother?
Extra great for FPS games like Jedi Knight and Elite Force; the two extra buttons are a big plus and you can scroll through weapon choices with the scroll ring.
Pros nice heavy trackball is as close to arcade as you can get without getting an actual arcade trackball. Four buttons gives a lot of flexibility in computer games.
Cons: wireless version needs batteries; easy to hit scroll ring in frenetic FPS games and change weapons inadvertantly; button action is not arcade, so likely needs to be combined with keyboard for gaming. It's a bit pricy compared to cheaper units.
Logitech Dual Action GamepadWell, on impulse I bought one in Maplin for £20. Much better than the Wingman, although also much lighter weight (probably because there's no useless rumble motors inside). It's also lighter weight than a standard Playstation controller; the plastic is definitely lighter weight and not as thick. The pad has a pretty good feel to it; buttons are laid out in a standard Playstation scheme, but with numbers instead of shapes. Bonus is that the buttons come up in Mame numbered as they are on the face of the controller. There are buttons in the Select and Start positions, but they are non-descript and numbered 9 and 10. The thumbsticks also have buttons for a total of twelve, but in pratice I found it impossible to assign the thumbstick buttons a function without also hitting a direction, so I finally gave up. I don't actually use the thumbstick buttons to date, but if you do, it's something to keep in mind.
Unlike the shiny surfaces of the playstation controller, the Dual Action has a matte surface, so if you get sweaty hands, this will probably help you keep a grip on the controller. As Vas stated, the only other issue is the imprecision of the d-pad. It's basically the same as on the Wingman and it can be tricky to define it initially as diagonals are easy to hit accidentally, but in actual use it's not too bad and there are raised bits at the cardinal directions which help hit the four-way points better.
Pros: Inexpensive, works right out of the box. If you swap back-and-forth with a playstation pad, the analogue sticks have the same values, so only the buttons and d-pad need to be redefined. Good action on the buttons and sticks.
Cons: square frame around analogue sticks makes calibration not quite as easy with the playstation controller. Easy to accidentally hit the diagonals with the d-pad. Thumbstick buttons difficult to hit precisely.