I too only recall seeing fast-track arrivals at Heathrow. (I haven't been to Kuala Lumpur recently.) Most airlines give the cards to the first- and business-class passengers before arrival on long-haul flights. I don't think that they are generally given out on short-haul flights, which is inherently illogical since passport queues can be just as long after those flights.
I'd have to say that sometimes it is faster and sometimes it isn't. Usually, though, I think it is, and I guess it is never likely to be grindingly slow – although there are usually only a couple of passport officers so it would just take two long, complicated interviews to block the whole queue.
I have seen fast-track passport control on exit at Sydney, certainly at the exit that leads to the lower gate numbers. When I used it in January it was certainly slower than the ordinary queue.
