If you use the brake all the time it will save your brakes, as well as keep things free and working (in the exhaust brake catagory)

 

I found that when I didn't use the exhaust brake for quite some time that the butterfly shaft got corroded and wouldn't function well...I had to remove it and work it over to get it all freed up and smooth. Use your e-brake often to keep it in good order. I use mine on snow and ice (I live in the Cascade Mountains where we get rain, ice, snow) and you just have to pay attention just as any other driving situation. It works fine in these conditions...just be on top of everything all the time. With my 6spd it works all the way down in mph with no "lower limit". I come off the passes fully loaded in 5th gear with the e-brake and NEVER use my trucks brakes. It is my favorite truck option.
Dondi