380/773 (or refurbed 772) Y is the best Y product in the fleet.

747/772 old Y is just ... old.

787 Y is too narrow, particularly 787-800.

WTP is excellent for a day flight at the right price - fixed sides on the seats can be restrictive for sleeping, which is a concern on night flights. Sadly SA is a night flight both ways but there's little that can be done about that.

But A380s are my favourite, I think, overall (across all cabins): (though the upper deck of a 747 may be better, and the 787 in WTP/J): guaranteed new economy product, almost no chance of a 772 substitution, and not too narrow or cramped, and not a 'dormitory' in business class.