I've used them exclusively in Polaris/Cat/Doo motors since about 2001. I've never had a failure in litterally a couple of hundred sets I've installed. I would use them in any motor except for the 05/06 900 Polaris, I'd use the stock OEM pistons in that motor.
Had them in my Rev 800 that had some mod work done, they worked awesome and still looked brand new even after 2 crank failures in 300 miles. Wouldn't hesitate to run them again.
Have had really good luck with SPI. They had some supply issues last year, and we couldn't get them, but all in all a good pistons. TiMoly is the one you want.