Going with an open vent with a filter on it is probably the best solution. Get away from the one-way spring loaded vent which can stick. If they would have used a Teflon seal instead of rubber in the vent, it probably wouldn't stick and have problems. The rubber tends to stick, and then the differential builds up lots of pressure and will finally make the vent pop open and puke oil out.
There's a thread or two in the Tech forum I believe that talks about using an open vent to cure the puking.