I am overwhelmed by conflicting reports on these cards on Trip Advisor! DH and I are going to Berlin with the 3 kids (13, 11 and 5) for 2.5 days. We've booked a bike tour round the city, but will probably go into a couple of museums - Pergamon and maybe HausamCheckpoint Charlie - is worth buying one of these cards? I am veering towards the Welcome card - any advice gratefully received.