i would advise your friends not to rush to get a wooden 1, whilst they of course look very nice and do the job they are both heavier and not as durable as an aluminium frame 1 - certainly if i was buying another 1 i wouldn't buy a wooden 1.
thats a load of rubbish - I've a lovely ply wood one and its fine!
they're hardy cycling it up hill so I weight is an issue
Wood is so much nicer a material than some horrible metal thing rusting away in the garden
And I dont think the metal balance bikes are alu - I suspect steel
Whats with using 1 instead of one?