It might help by mentioning where your friends will be flying from as well. Obviously if they're flying from somewhere like LAX then it's a bit of a detour taking Malaysian rather than Qantas and this should be factored into their plans. Flying from Europe on the other hand is basically the same when it comes to flight times between the two airlines.
Malaysian has good legroom in Economy class, 34" pitch or so, rather than Qantas and their 31" pitch which can be a bit snug. Service is good on Malaysian as well, and their entertainment systems are decent too. If mileage isn't of a concern for your friends, then Malaysian is a good option (and a stopover in Malaysia is worthwhile too - MAS usually has good packages available, certainly worth investigating if your friends have any interest at all in seeing that part of the world).