Setting up the XFPS isn't difficult at all. Just plug it into your 360, attach a wired controller, mouse, and keyboard to the XFPS, and turn on your 360. Once enabled, the XFPS has a standard keyboard and mouse layout, or you can choose to map buttons yourself. To map buttons, you need only tap the program button, the button you want to map on the 360 controller, and the corresponding button on the keyboard or mouse. For example, to map the shoot command to your left mouse button: tap the program button, pull the right trigger on your control, and click the left mouse button. Done. The XFPS only has two USB slots and the controller takes up one of those, so we're not really sure how you program your mouse and keyboard if they're both USB, though it is possible to use the default scheme. To use a Dual Shock (even a PS1 Dual Shock will work) all you have to do is plug it in. The Dual Shock simply mimics the layout of the 360 controller (minus the guide button).
Now for the test. We used three games: Gears of War (duh), Halo 2, and Rainbow Six: Vegas (demo version). Gears of War did not work well at all with the XFPS. Foregoing accuracy for now, let's focus on one thing: Gears was designed from the ground up as a 360 title. For instance, the "roadie run" uses the A button, which requires you to take your thumb off the right stick. To compensate for this, rotation control moves to the left stick during the roadie run. If you're using a keyboard however, you're stuck holding down a key and manipulating the WASD keys. It's awkward and in no way superior to a pad. Things like this make playing Gears a chore. Halo 2 played the best of the three games. It seems like the default keyboard layout was designed with Halo 2 in mind. Again though, issues pop up. For example, you won't be sneaking much, because keyboards have no analog support. Vegas, again, has similar issues.
Of course, we're sure PC diehards could live with these issues as long as they get their accurate mouse aiming. It's a shame, then, that aiming with the mouse is nigh impossible. Put simply, the mouse aiming sucks, no matter what sensitivity you choose in the game. It's jerky, and minute corrections -- the kind you need to make headshots -- don't work at all. Games that have multiple degrees of sensitivity -- like Vegas and Halo -- work somewhat better, but games with only low, medium, and high settings don't work nearly as well. By the time we popped in Vegas -- a game where every shot counts --it became readily apparent that the XFPS was not the solution that FPS players were looking for. There's always the chance that it might work better with a different mouse, but we doubt it. The simple truth is that 360 games were designed for analog sticks, and trying to emulate those with a mouse doesn't work -- at least not with the XFPS.
Also worth mentioning, there seemed to be a slight delay between button presses and the corresponding game action. Again, this is a huge no-no for pro FPS players. Last, but definitely not least, we were completely unable to use our headset while using our XFPS. We plugged the headset into the XFPS connected controller and the headset simply wasn't recognized. This issue might be averted if you have a wireless headset -- they connect to the 360 itself, not the controller -- but we didn't have one to test.
Before you stop reading this, it's not all bad. As a Dual Shock adapter, the XFPS positively excels. We played through a level of Assault Heroes and had no problems with it whatsoever. The d-pad worked well for Pac-Man, too, and it might improve your Street Fighter prowess if you were raised on Playstation. Hell, it even makes a decent controller for Gears. There are no obvious deficiencies of any kind actually -- apart from the lack of voice, of course. So, if you prefer Dual Shock (why?), the XFPS is a great adapter. It's easily the best feature of the XFPS.
So, final thoughts. The XFPS is a non-choice if you want to enjoy FPS games as they are on the PC; 360 games just weren't designed for it. There is no voice support -- a problem for all those team oriented FPS games you want to play. Sorry, FPS fanboys, the XFPS is not your dream device. As a Dual Shock adapter, on the other hand, the XFPS is fantastic. Still, $80 is pretty steep if all you're after is a Dual Shock adapter. However, if Team Xtender wanted to release a cheaper version that only supported the Dual Shock (and the SEGA Saturn pad while they're at it), we'd buy it. As it stands, the XFPS offers not much bang for an awful lot of bucks.