Vacuum pumps are the best way to go in terms of power. They are very expensive to setup and there are some issues with longevity on the street.
Pan evac systems (valve covers plumbed to headers) work great on open header race cars and nothing else. You may have seen someone run this on the street but rest assured that you had a better system with your stock PCV setup. This system relies on the high velocity exhaust gases exiting the the atmosphere at atmospheric pressure to create a pressure drop at a point tapped into the collector. This does not work if the collector does not exit to atmospheric pressure due to backpressure in the system. Even if you run sewage pipe there's going to be more backpressure than if it were open. The result is the valve in the collector shuts and you have no crankcase ventilation when you most need it (under load). In street cars I've seen this result in oil past the rear main seal.
If I can't run a vacuum pump my second choice would be a stock type PCV system. Many years ago I had a 350 Chevy running open breathers on either valve cover. I started to get white stuff under the valve covers (moisture) and sometimes I saw smoke under load. This prompted me to switch to a stock PCV setup. Either system resulted in 12.50s @ 108 (give or take) at the dragstrip so I can't say that there was an performance difference. My car never smoked again, inside my engine was spotless, and I gained a BIG notice in driveability down low. This was a daily driver though. The buildup probably wouldn't be so bad if the car was driven less.
With a PCV system you use manifold vacuum like you would an accessory, so this cost power, and you contaminate your intake charge. The plus side is that you apply a vacuum to the crankcase, which has been proven to add horsepower (and keep things clean!). The open breather setup doesn't use manifold vacuum so therefor doesn't add any contamination, but you NEVER pull a vacuum on the crankcase. Also, a poorly ventilated crankcase will eventually add contamination to the intake charge so that difference really doesn't come into play. The crankcase is always at a higher pressure than atmospheric (otherwise nothing would vent out). As mentioned above, vacuum on the crankcase adds power. Marginally in the case of a PCV system when compared to the big power a vacuum pump can add, but the effect is the same. The best way to run a PCV system is where you apply manifold vacuum to one valve cover (or where ever you want to vent from, valley pan on some motors), and run the other valve cover to the air cleaner/inlet. This uses the venturi effect of the entering air to pull a vacuum on the crankcase when the manifold vacuum drops, so you always have a vacuum whether your load is low (high manifold vacuum), or your load is high (large amount of air entering, large pressure drop (vacuum) in air inlet). Some people run PCV with a breather which isn't nearly as efficient. It's best to keep the system closed.
I agree, this is an interesting topic that isn't really discussed very often. Leads to alot of confusion about what is really going on for some people. I'd love to see a dyno test running a stock PCV system against an open breather on each valve cover. But I'm sure the .05% difference wouldn't be that interesting to people, and the hot rod magazines aren't in business to tell people to leave their stock stuff alone.
