My Walther P99 in .40S&W is my primary defense gun, and I also used it in IDPA matches. The .40 is a bit snappy, and tough to get fast splits, so it is not ideal for action pistol matches. But it is also not atrocious either.
I find that for being a 4" barrel, it is exquisitely accurate. I am as accurate with it as I am with my 5" XD Tactical in 9mm.
Before I switched to the XD, I was winning SSP Marksman division in most of my local matches, and I have classified as an SSP Sharpshooter with the gun. But it is just a little too much recoil for me to win Sharpshooter at most matches (note that I don't reload, so I can't cook up .40 with milder properties).
I bought mine online through GunBroker.com.
Best,
Jim