Doing the same thing here as Goldgiggie. I use that brewershardware cap, and love it.
Pushing out the finished beer under pressure instead of siphoning is so nice, I can't even describe it.
Make sure you have a good plan to clean our your sanke. I do oxy-clean and blindly scrub with a carboy brush. Then on brew day, boil a gallon of water with some tinfoil wrapped over the top to push the steam down around the opening. Let it cool throughout the day as you brew, and pour the boiled water out right before you use it.
Haven't had a problem yet.
Oh, one more thing. You will notice a marked improvement in upper-body strength after a few months of using sankes like this. Trust me.