Marc s
NASA AIX
The only issue I have with all those breathers is they tend to "drip" oil from time to time. I'd much prefer to run the separator/breather that Mark has on his. My inline catch can does a pretty good job, but I intend on running the same setup as Mark.
That's exactly why I didn't use valve cover breathers. Also, the tank is fairly inexpensive. I also re-used the ends off of the factory lines for a cleaner look.
http://www.summitracing.com/parts/AAF-ALL36109/