Originally Posted by Mr H

You cannot transfer miles from LH to BD - they are stuck with whichever card you put them on. With Star Alliance airlines, you can claim miles on any * flight on any * frequent flyer scheme. Which one is best for you depends on what you want to get, what your flyer patterns are and a range of other personal things. If you usually fly in economy and fly enough to get to silver status, then you're probably best off joining the programme of the airline you fly with most often as that's the only one you'll get lounge access for. If you fly enough to get to gold (or fly in premium cabins) then lounge access is available on all * airlines, so you'd then want to start looking at earning and redemption rates.