Right or wrong, as I've mentioned in previous threads CX has lost a decent chunk of my premium cabin business flying to SIN as a result of the swaps.
SQ you can guarantee long haul J and F.
CX you can't.
In the last twelve months I've done 5 Singapore round trips from HKG. 2x on CX and 3x on SQ. 3 in J and 2 in F. Here's a helpful breakdown for the CX beancounters:
CX: 2x Asia Miles mileage redemption J tickets.
SQ: 1x cash J ticket, 2x cash F tickets.
The fact CX "usually" has a predictable product is useless. Because it's the fact you COULD be swapped out which is the issue. Somewhat tragic too, because I find the CX 35G J class a lovely regional product, especially with WiFi for productivity. I probably would've just paid cash for all the J class tickets on CX if I could absolutely guarantee the 35G or a wifi-equipped 77W when that happens. But you can't.
And like we all know, you can't guarantee F to SIN either (that's an even-more-likely equipment swap).