About the controller
The first thing you'll notice about the Freestyle Pro is how comfortable it is. Unlike the older SideWinder gamepad, it's designed with an eye on ergonomics, and it fits quite well in the hand. The large handles on each side are contoured so that the controller naturally rests at a neutral, flat angle, with your index fingers on the two large front triggers and your two thumbs poised over the buttons and pad respectively. This is, flat out, the most comfortable gamepad I've tried on the PC. The only concern here is that the controller feels a bit large; if you have small hands, you may want to try it on for size beforehand.
Ergonomics aside, the button complement is fairly standard for a modern gamepad, and almost identical to the original SideWinder gamepad. There are six buttons on the right side of the controller, two front triggers, a "shift" button and a "start" button. The only addition is a texturized rubber throttle wheel in the middle of the controller. The throttle works well, but it has no start and end detents, which can feel strange. You can keep spinning it in place even when you are at maximum throttle in a game, for example.
The Freestyle Pro is one of the very few SideWinder controllers that works as a USB device. It's a bit odd that Microsoft, usually a technology leader, does not support USB across all of their new controllers. The connecting cable ends in a standard gameport header, but there is a short conversion cable that converts the cable into USB. It's a little annoying that Microsoft didn't end the cable in a USB header, since the heavy gameport-to-USB conversion cable adds a lot of pointless weight to the end of the USB cable right next to where the cable will be connected to your computer. At any rate, it's nice to have the ability to use a gameport connection for older PCs, and USB for newer PCs.
Of course, these are all standard gamepad PC features nowadays. There's a reason the code name for this controller while under development was "Tilt": the real claim to fame of this controller is its tilt feature. The Freestyle Pro by default operates in an analog mode where it can actually sense how far you have "tilted" the controller, both left-to-right and front-to-back, providing your analog X and Y axis control for gaming. Alternately, you can switch the controller to a digital mode where it acts exactly like a standard digital gamepad. The tilt is an exciting feature, but it's hard to talk about without referencing actual games, so I will get to that a bit later.