Switzerland-Murren-Jungfrau: Swiss Pass? Railpass?

Swiss Pass will cover all the way from Zurich -> Luzern -> Interlake -> Lauterbrunnen -> Wengen for free. From there to the Jungfrau you can expect a 50% discount.

A General Abonnement Swiss pass (not a Eurail pass) will get you to Lauterbrunnen, Wengen, Gimmelwald and Muerren without additional cost. It will also get you to Grindelwald from Interlaken. You are fully covered for these places. Of course, there is the 1/2-fare Swiss pass which covers 50% of every fare.

As you go above Wengen on one side of the valley or Gimmelwald or Muerren on the other, the GA Swiss pass gets you a 50% discount. Same with the 1/2-fare Swiss pass.

The current fare to go from Lauterbrunnen to the Jungfraujoch is about 170CHF (Swiss Francs). With the Swiss Franc roughly equal to a dollar, this is a $170 round trip per person. Again, your Swiss passes will get you a 50% discount. The fare from Lauterbrunnen to the top of the Shilthorn is about 116CHF.

If I have a railpass instead of a swiss pass (seems like it wouldn't make much sense to get both), do I get about as much of a discount? ie what are the primary benefits of the swiss pass over the rail pass?

Personally I think the Swiss Pass is very convenient to use because you can just hop on any train, bus, boat, gondola, cogwheel any time anywhere as many times as you look during the validity period. Probably the best reason to get a Swiss Pass is for the discounts on the high mountain railways which are rather expensive. Places like the Jungfrau, Schilthorn, Matterhorn all offer 50% discount with the Swiss Pass. There may be some discount with a Eurail Pass, but it will not be as much as a Swiss Pass discount - if any at all. A list of other benefits offered with a Swiss Pass can be found here: http://myswitzerland.raileurope.com/us/rail/passes/bonuses/swiss_passes.htm

There is no contest that in Switzerland, the Swiss pass is the way to go. The Swiss pass is much better than the Eurail pass. Additionally, on any transit system (train, cog train, gondola, etc.) in the Lauterbrunnen valley, the Eurail pass will only get you a 25% discount on all fares. On the bus, it gets you nothing. As I mentioned above, the Swiss Pass fully covers you up to Lauterbrunnen, Wengen, Gimmelwald and Muerren and provides a 50% discount to go higher. There is quite a cost difference if you plan on going to the Jungfraujoch or the Shilthorn.

I see that the swiss pass also provides a discount on CNL night trains. I planned to take the CNL from Amsterdam to Zurich to come to Switzerland, and probably the EuroNight Luna to leave Switzerland. Would the Swiss Pass provide good discounts on these?