London pass vs Oyster Card

What do you mean by a "London Pass"?
In order to get through the ticket barriers into the tube, or board a bus in London you either need an Oyster card, or you buy a ticket. An Oyster card is a smart card which you hold in front of the reader, it goes "Beep" and the barrier opens or the driver lets you on the bus. Tickets can only be bought at stations, NOT on buses.

You can either pre-load cash on an Oyster card, in which case it deducts the fare every time, and shows how much is left on the display; or you can pre-pay for a week or longer, and load the "pre-paid" travelcard on the Oyster card.
The pre-pay method has two big advantages:
(1) it is about 50% of the cost of buying a ticket at the ticket machine for every trip.
(2) When you reach a certain figure every day (equivalent to about 3-4 rides), it stops charging you and the rest of the day is free. This is known as "capping".
Cards can be re-loaded at stations and many local shops (look for sticker in window).

You can pre-pay a 7-day travelcard and load it on your Oyster card. This is cheaper than 7 x 1-day capped fares.

The price comparison is here.

CONCLUSION: buy an Oyster card. If you are in London and travelling for 7 days, buy a 7-day travelcard on your Oyster (one valid out to Leytonstone). If you are there for less than 7-days, just put £20-£30 on it, and when it runs down re-load it.

For full details see the official "Transport for London" website.

Note that weekly capping is offered if you use your own contactless credit / debit card on a Monday to Sunday basis rather than an Oystercard. Depends what card you have whether this will work.

Are you going to zone 1 ie central London every day?

The London Pass, which covers many big sights and lets you skip some lines, is expensive but potentially worth the investment for extremely busy sightseers (£47/1 day, £65/2 days, £78/3 days, £104/6 days; days are calendar days rather than 24-hour periods; comes with 160-page guidebook, also sold at major train stations and airports, tel. 0870-242-9988, www.londonpass.com). Among the many sights it includes are the Tower of London, Westminster Abbey, Churchill War Rooms, and Windsor Castle, as well as many temporary exhibits and audioguides at otherwise “free” biggies. Think through your sightseeing plans, study their website to see what’s covered, and do the math before you buy.

London has the most expensive public transit in the world--save money on your Tube rides using a multiride pass. You have two good options: Get a Travelcard for unlimited travel; these are available in one-day and seven-day versions. Or buy a £5 Oyster card and top it up as needed to travel like a local for about £1-2 per ride.

Wondering which pass works best for your trip? On a short visit (three days or fewer), if you think you’ll be zipping around a lot, consider a One-Day Travelcard for each day you’re here (or at least for your busiest days); if you’ll be taking fewer rides, get an Oyster card (described above) and pay as you go. If you’re in London for four days or longer, the Seven-Day Travelcard will likely pay for itself.

London has the most expensive public transit in the world

I don't know WHERE myths get started, but surely the role of a Rick Steves' ETBD staffer, representing all the credibility and good will of the Rick Steves organization, is not to exaggerate.

Has anybody priced the trains around Lauterbrunnen recently, on a per mile basis? I can get all the way across London and back for what it would cost me to go from Lauterbrunnen via Grutschalp to Muerren on what is based on a rail fare (the gondola up from Lauterbrunnen replaces a funicular and is still priced that way), or the train to Jungfraujoch?

London is not cheap, but it is not the most expensive in the world.

For the other question - do the maths and decide if the included places are worth the high price for the Pass - remember that many of the listed places are free anyway and the Pass only provides a headset or temporary exhibit (ask yourself if you really want or have time for the temporary exhibit).

Most reporters have reported a loss using the London Pass - certainly a zone 1-4 weekly season ticket on an Oyster should provide virtually all the transport you need.

As far as using your foreign contactless card - be very careful. Advertising from TfL warns people using foreign cards to be aware of the policies of the card issuers, particularly in relation to FTF fees and exchange rates.

Personally I think London's public transportation is reasonably priced. If you want to see expensive - look at the Washington, DC Metro system! Sorry, I know that was completely off topic to the original question.

As earlier posters have advised, go with the Oyster Card and put a 7-day travelcard on it. The London Pass looks good at first glance, but when you do the math for the places you intend to visit that charge admission, I think you'll find at best you MIGHT break even.