I don't know where you are riding, but I have ridden a lot of miles on these machines including a 2004 sportsman 600 and never lost the brakes. This system has been in use since Polaris started making ATVs so I don't see the need to change it. Make sure your brake lines are in good shape and protect them as best you can then go riding!
I'm not just talking from a loss of brake issue, but that is still an issue. I've put many thousands of miles on all sorts of machines. Harleys that I've built from the frame up to a Hayabusa. Camaros, Mercedes, F350 trucks, snowmobiles and more than 30 different dirt bikes over the 40 years that I've actually been ripping up the dirt and pavement. My last off road bike was a KTM 300 2 stroke. This is my first real quad though. I just don't like the Polaris brake system. I want to be able to use the rear brake separate from the front brakes. They should be two separate systems IMO.