Reply to "Valve cover breathers / PCV advice"

Any liquid, vapor or air that is in the hose from the pcv valve on the right, has to make its way up to the holes in the circle. You could get some liquid collecting in that hose but as the hose is under vacuum from the engine it will just suck it into the separator. The separator is not very large and need to empty it before it gets too close to the filter, going fast around the twisty's does not help.
There is no one-way built into the separator I don't think you need one. The oil level would have go all the way to the holes circled for it to drain back into the supply hose. The engine vacuum would suck the oil into engine before then.
JTpantera does not look to have an issue with engine moisture, but up in the colder places you might see a more browny mixture. We recently put a turbo on my son's Focus and we used the air / water separator to diagnose we were have serious oil loss through the stock pcv system. We then went to a similar catch can that Doug is using. In the freezing cold weather we are having, it completely freeze the vent lines and can. Oil blew past the rings, up through the drain lines for the turbo into turbine and compressor. Not pretty. They do make heated catch cans that have hot water fittings on them to prevent this.
It is best to mount catch can as high up as possible in the engine bay to allow drain back and stop too much oil being sucked out.
If you can use the stock system it is certainly the simplest but it can cause problems in some situations.