At forty bucks US, fifty Cdn, Microsoft's SideWinder X3 Mouse is certainly "affordable" - a tad pricier than a "regular" mouse but less than most gamer-class pointing devices, which run from about $50 up to some $150 for the hardcore Uber rodents.
As a gamer specific mouse, the X3 features 2,000 dots-per-inch (dpi) laser-tracking with on-the-fly adjustability, plus wide, slick-glide "feet" that make it easy to whip around, all of which you'd expect.
The Sidewinder X3 also features 5 programmable buttons, though only the two on either side seem ripe for remapping... unless you don't think the ol' left click, right click, middle button/scroll are particularly useful.
Similarly, the entirely awesome ability to adjust sensitivity on-the-fly is befuddled by the fact that you can only adjust in increments of 400 dpi, and only to the tune of three different presets in three topside buttons. Essentially, this gives you real-time, in-game access to preferred speed, way too slow, and, quite literally, utterly retarded. Yeah, that's a good setting.
Any gamer grade mouse worth its salt allows for on-the-fly sensitivity adjustments spanning a huge swath of the dpi spectrum in increments of 50, 10, or even 1 dpi (as is the case with SteelSeries' Ikari Laser Mouse). Such functionality lets you rapidly adjust your free-look and/or aiming capabilities to the precision context of the game, the situation or the weapon/device in (virtual) hand. The X3 does not.
Where the X3 truly fails to impress in its loudly touted "ambidextrous" form factor. While a lefty-friendly mouse might pique the interest of left-handed users, give it but a moment's thought and you'll realize the very idea is just plain stupid.
Ford doesn't put a gear shift in the driver's side door of a car just to accommodate lefties, nor does Hilroy make binders and looseleaf for the right-brain incline. Baring a right-hand injury or disability, a southpaw mouse makes no sense.
Sure, lefties are a lot smarter and way better looking than righties (note: the author is a lefty), but unless you're living in a bubble, a left-handed mouse habit is going mess with your bubblehead every time you use the shared computer at an internet cafe, the office, a friend's house or anywhere else other than your bubble. People borrowing your computer will be conversely befuddled and start calling you a noob behind your back. Or they'll try to sell you a left-handed monkey wrench... You should so buy it!
Besides, the X3's ambidextrous housing also gives it all the shapeliness of a convex brick, and all the ergonomic comfort of fondling one, too.