I have owned a Shadow (not the 2), Stock 3 and 2. While you obviously can make it to the top in IPSC with any of these guns here is the advice I got when asking about the Shadow 2 from a very capable guy who knows these guns inside out....
"Shadow has a better safety design (doesn't break and has a dedicated detent part that cams on the safety rather than the frame), better trigger due to longer mainspring and better trigger bar lifter design. Frame is heavier in the area of the safety and the sear cage and doesn't crack. Sights are sturdier. Barrels last longer and a fitted better, generally, so lugs last. All kinds of Production-legal CZ upgrades are available. The Pre-B disconnector is especially sweet, yielding a reset like a 1911.
Shadow 2 has all of that plus a forged frame and slide, checkering on front and back strap, extended mag release, well made adjustable sights, much better finish, longer barrel and frame which puts more weight up front for recoil dampening.
If I were buying a Production gun right now it would be a Shadow 2. Hands down, it is the best of all available options."